diff --git a/TypeScriptReact.YAML-tmLanguage b/TypeScriptReact.YAML-tmLanguage
index a8ec19cc..024ecd6d 100644
--- a/TypeScriptReact.YAML-tmLanguage
+++ b/TypeScriptReact.YAML-tmLanguage
@@ -34,25 +34,29 @@ repository:
     begin: |-
       (?x)
         (?<=[({\[,?=>:*]|&&|\|\||\?|{{lookBehindReturn}}|{{lookBehindDefault}}|^)\s*
-        (?=(<)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>))
-    end: (?!\s*(<)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>))
+        (?=(<)\s*(?:([_$a-zA-Z][-$\w.]*)(?<!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>))
+    end: (?!\s*(<)\s*(?:([_$a-zA-Z][-$\w.]*)(?<!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>))
     patterns:
     - include: '#jsx-tag-without-attributes'
 
   jsx-tag-without-attributes:
     name: meta.tag.without-attributes.tsx
-    begin: (<)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>)
-    end: (</)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>)
+    begin: (<)\s*(?:([_$a-zA-Z][-$\w.]*)(?<!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>)
+    end: (</)\s*(?:([_$a-zA-Z][-$\w.]*)(?<!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))?\s*(>)
     beginCaptures:
       '1': {name: punctuation.definition.tag.begin.tsx}
-      '2': {name: entity.name.tag.tsx}
-      '3': {name: support.class.component.tsx}
-      '4': {name: punctuation.definition.tag.end.tsx}
+      '2': {name: entity.name.tag.namespace.tsx}
+      '3': {name: punctuation.separator.namespace.tsx}
+      '4': {name: entity.name.tag.tsx}
+      '5': {name: support.class.component.tsx}
+      '6': {name: punctuation.definition.tag.end.tsx}
     endCaptures:
       '1': {name: punctuation.definition.tag.begin.tsx}
-      '2': {name: entity.name.tag.tsx}
-      '3': {name: support.class.component.tsx}
-      '4': {name: punctuation.definition.tag.end.tsx}
+      '2': {name: entity.name.tag.namespace.tsx}
+      '3': {name: punctuation.separator.namespace.tsx}
+      '4': {name: entity.name.tag.tsx}
+      '5': {name: support.class.component.tsx}
+      '6': {name: punctuation.definition.tag.end.tsx}
     contentName: meta.jsx.children.tsx
     patterns:
     - include: '#jsx-children'
@@ -64,16 +68,19 @@ repository:
         (?<=[({\[,?=>:*]|&&|\|\||\?|{{lookBehindReturn}}|{{lookBehindDefault}}|^)\s*
         (?!<\s*[_$[:alpha:]][_$[:alnum:]]*((\s+extends\s+[^=>])|,)) # look ahead is not type parameter of arrow
         (?=(<)\s*
+        ([_$a-zA-Z][-$\w.]*(?<!\.|-):)?
         ([_$a-zA-Z][-$\w.]*(?<!\.|-))
         (?=\s+(?!\?)|/?>))
-    end: (/>)|(?:(</)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))\s*(>))
+    end: (/>)|(?:(</)\s*(?:([_$a-zA-Z][-$\w.]*)(?<!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))\s*(>))
     endCaptures:
       '0': { name: meta.tag.tsx }
       '1': { name: punctuation.definition.tag.end.tsx }
       '2': { name: punctuation.definition.tag.begin.tsx }
-      '3': { name: entity.name.tag.tsx }
-      '4': { name: support.class.component.tsx }
-      '5': { name: punctuation.definition.tag.end.tsx }
+      '3': { name: entity.name.tag.namespace.tsx }
+      '4': { name: punctuation.separator.namespace.tsx }
+      '5': { name: entity.name.tag.tsx }
+      '6': { name: support.class.component.tsx }
+      '7': { name: punctuation.definition.tag.end.tsx }
     patterns:
     - include: '#jsx-tag'
 
@@ -82,16 +89,19 @@ repository:
     begin: |-
       (?x)
         (?=(<)\s*
+        ([_$a-zA-Z][-$\w.]*(?<!\.|-):)?
         ([_$a-zA-Z][-$\w.]*(?<!\.|-))
         (?=\s+(?!\?)|/?>))
-    end: (/>)|(?:(</)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))\s*(>))
+    end: (/>)|(?:(</)\s*(?:([_$a-zA-Z][-$\w.]*)(?<!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))\s*(>))
     endCaptures:
-      '0': { name: meta.tag.tsx }
-      '1': { name: punctuation.definition.tag.end.tsx }
-      '2': { name: punctuation.definition.tag.begin.tsx }
-      '3': { name: entity.name.tag.tsx }
-      '4': { name: support.class.component.tsx }
-      '5': { name: punctuation.definition.tag.end.tsx }
+     '0': { name: meta.tag.tsx }
+     '1': { name: punctuation.definition.tag.end.tsx }
+     '2': { name: punctuation.definition.tag.begin.tsx }
+     '3': { name: entity.name.tag.namespace.tsx }
+     '4': { name: punctuation.separator.namespace.tsx }
+     '5': { name: entity.name.tag.tsx }
+     '6': { name: support.class.component.tsx }
+     '7': { name: punctuation.definition.tag.end.tsx }
     patterns:
     - include: '#jsx-tag'
 
@@ -100,19 +110,23 @@ repository:
     begin: |-
       (?x)
         (?=(<)\s*
+        (?:([_$a-zA-Z][-$\w.]*)(?<!\.|-)(:))?
         ([_$a-zA-Z][-$\w.]*(?<!\.|-))
         (?=\s+(?!\?)|/?>))
-    end: (?=(/>)|(?:(</)\s*([_$a-zA-Z][-$\w.]*(?<!\.|-))\s*(>)))
+    end: (?=(/>)|(?:(</)\s*(?:([_$a-zA-Z][-$\w.]*)(?<!\.|-)(:))?([_$a-zA-Z][-$\w.]*(?<!\.|-))\s*(>)))
     patterns:
     - begin: |-
         (?x)
           (<)\s*
+          (?:([_$a-zA-Z][-$\w.]*)(?<!\.|-)(:))?
           ((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?<!\.|-))
           (?=\s+(?!\?)|/?>)
       beginCaptures:
         '1': { name: punctuation.definition.tag.begin.tsx }
-        '2': { name: entity.name.tag.tsx }
-        '3': { name: support.class.component.tsx }
+        '2': { name: entity.name.tag.namespace.tsx }
+        '3': { name: punctuation.separator.namespace.tsx }
+        '4': { name: entity.name.tag.tsx }
+        '5': { name: support.class.component.tsx }
       end: (?=[/]?>)
       contentName: meta.tag.attributes.tsx
       patterns:
@@ -170,10 +184,13 @@ repository:
     match: |-
       (?x)
         \s*
+        (?:([_$a-zA-Z][-$\w.]*)(:))?
         ([_$a-zA-Z][-$\w]*)
         (?=\s|=|/?>|/\*|//)
     captures:
-      '1': {name: entity.other.attribute-name.tsx}
+      '1': {name: entity.other.attribute-name.namespace.tsx}
+      '2': {name: punctuation.separator.namespace.tsx}
+      '3': {name: entity.other.attribute-name.tsx}
 
   jsx-tag-attribute-assignment:
     name: keyword.operator.assignment.tsx
diff --git a/TypeScriptReact.tmLanguage b/TypeScriptReact.tmLanguage
index 6339e476..2d6ca777 100644
--- a/TypeScriptReact.tmLanguage
+++ b/TypeScriptReact.tmLanguage
@@ -6897,9 +6897,9 @@
         <key>begin</key>
         <string>(?x)
   (?&lt;=[({\[,?=&gt;:*]|&amp;&amp;|\|\||\?|^return|[^\._$[:alnum:]]return|^default|[^\._$[:alnum:]]default|^)\s*
-  (?=(&lt;)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))?\s*(&gt;))</string>
+  (?=(&lt;)\s*(?:([_$a-zA-Z][-$\w.]*)(?&lt;!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))?\s*(&gt;))</string>
         <key>end</key>
-        <string>(?!\s*(&lt;)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))?\s*(&gt;))</string>
+        <string>(?!\s*(&lt;)\s*(?:([_$a-zA-Z][-$\w.]*)(?&lt;!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))?\s*(&gt;))</string>
         <key>patterns</key>
         <array>
           <dict>
@@ -6913,9 +6913,9 @@
         <key>name</key>
         <string>meta.tag.without-attributes.tsx</string>
         <key>begin</key>
-        <string>(&lt;)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))?\s*(&gt;)</string>
+        <string>(&lt;)\s*(?:([_$a-zA-Z][-$\w.]*)(?&lt;!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))?\s*(&gt;)</string>
         <key>end</key>
-        <string>(&lt;/)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))?\s*(&gt;)</string>
+        <string>(&lt;/)\s*(?:([_$a-zA-Z][-$\w.]*)(?&lt;!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))?\s*(&gt;)</string>
         <key>beginCaptures</key>
         <dict>
           <key>1</key>
@@ -6926,14 +6926,24 @@
           <key>2</key>
           <dict>
             <key>name</key>
-            <string>entity.name.tag.tsx</string>
+            <string>entity.name.tag.namespace.tsx</string>
           </dict>
           <key>3</key>
           <dict>
             <key>name</key>
-            <string>support.class.component.tsx</string>
+            <string>punctuation.separator.namespace.tsx</string>
           </dict>
           <key>4</key>
+          <dict>
+            <key>name</key>
+            <string>entity.name.tag.tsx</string>
+          </dict>
+          <key>5</key>
+          <dict>
+            <key>name</key>
+            <string>support.class.component.tsx</string>
+          </dict>
+          <key>6</key>
           <dict>
             <key>name</key>
             <string>punctuation.definition.tag.end.tsx</string>
@@ -6949,14 +6959,24 @@
           <key>2</key>
           <dict>
             <key>name</key>
-            <string>entity.name.tag.tsx</string>
+            <string>entity.name.tag.namespace.tsx</string>
           </dict>
           <key>3</key>
           <dict>
             <key>name</key>
-            <string>support.class.component.tsx</string>
+            <string>punctuation.separator.namespace.tsx</string>
           </dict>
           <key>4</key>
+          <dict>
+            <key>name</key>
+            <string>entity.name.tag.tsx</string>
+          </dict>
+          <key>5</key>
+          <dict>
+            <key>name</key>
+            <string>support.class.component.tsx</string>
+          </dict>
+          <key>6</key>
           <dict>
             <key>name</key>
             <string>punctuation.definition.tag.end.tsx</string>
@@ -6979,10 +6999,11 @@
   (?&lt;=[({\[,?=&gt;:*]|&amp;&amp;|\|\||\?|^return|[^\._$[:alnum:]]return|^default|[^\._$[:alnum:]]default|^)\s*
   (?!&lt;\s*[_$[:alpha:]][_$[:alnum:]]*((\s+extends\s+[^=&gt;])|,)) # look ahead is not type parameter of arrow
   (?=(&lt;)\s*
+  ([_$a-zA-Z][-$\w.]*(?&lt;!\.|-):)?
   ([_$a-zA-Z][-$\w.]*(?&lt;!\.|-))
   (?=\s+(?!\?)|/?&gt;))</string>
         <key>end</key>
-        <string>(/&gt;)|(?:(&lt;/)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))\s*(&gt;))</string>
+        <string>(/&gt;)|(?:(&lt;/)\s*(?:([_$a-zA-Z][-$\w.]*)(?&lt;!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))\s*(&gt;))</string>
         <key>endCaptures</key>
         <dict>
           <key>0</key>
@@ -7003,14 +7024,24 @@
           <key>3</key>
           <dict>
             <key>name</key>
-            <string>entity.name.tag.tsx</string>
+            <string>entity.name.tag.namespace.tsx</string>
           </dict>
           <key>4</key>
           <dict>
             <key>name</key>
-            <string>support.class.component.tsx</string>
+            <string>punctuation.separator.namespace.tsx</string>
           </dict>
           <key>5</key>
+          <dict>
+            <key>name</key>
+            <string>entity.name.tag.tsx</string>
+          </dict>
+          <key>6</key>
+          <dict>
+            <key>name</key>
+            <string>support.class.component.tsx</string>
+          </dict>
+          <key>7</key>
           <dict>
             <key>name</key>
             <string>punctuation.definition.tag.end.tsx</string>
@@ -7029,10 +7060,11 @@
         <key>begin</key>
         <string>(?x)
   (?=(&lt;)\s*
+  ([_$a-zA-Z][-$\w.]*(?&lt;!\.|-):)?
   ([_$a-zA-Z][-$\w.]*(?&lt;!\.|-))
   (?=\s+(?!\?)|/?&gt;))</string>
         <key>end</key>
-        <string>(/&gt;)|(?:(&lt;/)\s*((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))\s*(&gt;))</string>
+        <string>(/&gt;)|(?:(&lt;/)\s*(?:([_$a-zA-Z][-$\w.]*)(?&lt;!\.|-)(:))?((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))\s*(&gt;))</string>
         <key>endCaptures</key>
         <dict>
           <key>0</key>
@@ -7053,14 +7085,24 @@
           <key>3</key>
           <dict>
             <key>name</key>
-            <string>entity.name.tag.tsx</string>
+            <string>entity.name.tag.namespace.tsx</string>
           </dict>
           <key>4</key>
           <dict>
             <key>name</key>
-            <string>support.class.component.tsx</string>
+            <string>punctuation.separator.namespace.tsx</string>
           </dict>
           <key>5</key>
+          <dict>
+            <key>name</key>
+            <string>entity.name.tag.tsx</string>
+          </dict>
+          <key>6</key>
+          <dict>
+            <key>name</key>
+            <string>support.class.component.tsx</string>
+          </dict>
+          <key>7</key>
           <dict>
             <key>name</key>
             <string>punctuation.definition.tag.end.tsx</string>
@@ -7081,16 +7123,18 @@
         <key>begin</key>
         <string>(?x)
   (?=(&lt;)\s*
+  (?:([_$a-zA-Z][-$\w.]*)(?&lt;!\.|-)(:))?
   ([_$a-zA-Z][-$\w.]*(?&lt;!\.|-))
   (?=\s+(?!\?)|/?&gt;))</string>
         <key>end</key>
-        <string>(?=(/&gt;)|(?:(&lt;/)\s*([_$a-zA-Z][-$\w.]*(?&lt;!\.|-))\s*(&gt;)))</string>
+        <string>(?=(/&gt;)|(?:(&lt;/)\s*(?:([_$a-zA-Z][-$\w.]*)(?&lt;!\.|-)(:))?([_$a-zA-Z][-$\w.]*(?&lt;!\.|-))\s*(&gt;)))</string>
         <key>patterns</key>
         <array>
           <dict>
             <key>begin</key>
             <string>(?x)
   (&lt;)\s*
+  (?:([_$a-zA-Z][-$\w.]*)(?&lt;!\.|-)(:))?
   ((?:[a-z][a-z0-9]*|([_$a-zA-Z][-$\w.]*))(?&lt;!\.|-))
   (?=\s+(?!\?)|/?&gt;)</string>
             <key>beginCaptures</key>
@@ -7103,9 +7147,19 @@
               <key>2</key>
               <dict>
                 <key>name</key>
-                <string>entity.name.tag.tsx</string>
+                <string>entity.name.tag.namespace.tsx</string>
               </dict>
               <key>3</key>
+              <dict>
+                <key>name</key>
+                <string>punctuation.separator.namespace.tsx</string>
+              </dict>
+              <key>4</key>
+              <dict>
+                <key>name</key>
+                <string>entity.name.tag.tsx</string>
+              </dict>
+              <key>5</key>
               <dict>
                 <key>name</key>
                 <string>support.class.component.tsx</string>
@@ -7272,11 +7326,22 @@
         <key>match</key>
         <string>(?x)
   \s*
+  (?:([_$a-zA-Z][-$\w.]*)(:))?
   ([_$a-zA-Z][-$\w]*)
   (?=\s|=|/?&gt;|/\*|//)</string>
         <key>captures</key>
         <dict>
           <key>1</key>
+          <dict>
+            <key>name</key>
+            <string>entity.other.attribute-name.namespace.tsx</string>
+          </dict>
+          <key>2</key>
+          <dict>
+            <key>name</key>
+            <string>punctuation.separator.namespace.tsx</string>
+          </dict>
+          <key>3</key>
           <dict>
             <key>name</key>
             <string>entity.other.attribute-name.tsx</string>
diff --git a/tests/baselines/pr557_namespacedJsx.baseline.txt b/tests/baselines/pr557_namespacedJsx.baseline.txt
new file mode 100644
index 00000000..7d6ca57d
--- /dev/null
+++ b/tests/baselines/pr557_namespacedJsx.baseline.txt
@@ -0,0 +1,256 @@
+original file
+-----------------------------------
+// @onlyOwnGrammar - As this has jsx
+const valid1 = <standard-tag standard-attribute="foo" />;
+
+const valid2 = <namespaced:tag namespaced:boolean-attr>foo</namespaced:tag>;
+
+const valid3 = <namespaced:Klass.comp.onent namespaced:attr="foo" />;
+
+const invalid1 = <too:much:Namespace />;
+
+const invalid2 = <namespaced-:Klass.Component too:much:namespace-attribute>foo</namespaced-:Klass.Component>;
+-----------------------------------
+
+Grammar: TypeScriptReact.tmLanguage
+-----------------------------------
+>// @onlyOwnGrammar - As this has jsx
+ ^^
+ source.tsx comment.line.double-slash.tsx punctuation.definition.comment.tsx
+   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   source.tsx comment.line.double-slash.tsx
+>const valid1 = <standard-tag standard-attribute="foo" />;
+ ^^^^^
+ source.tsx meta.var.expr.tsx storage.type.tsx
+      ^
+      source.tsx meta.var.expr.tsx
+       ^^^^^^
+       source.tsx meta.var.expr.tsx meta.var-single-variable.expr.tsx meta.definition.variable.tsx variable.other.readwrite.tsx
+             ^
+             source.tsx meta.var.expr.tsx meta.var-single-variable.expr.tsx
+              ^
+              source.tsx meta.var.expr.tsx keyword.operator.assignment.tsx
+               ^
+               source.tsx meta.var.expr.tsx
+                ^
+                source.tsx meta.var.expr.tsx meta.tag.tsx punctuation.definition.tag.begin.tsx
+                 ^^^^^^^^^^^^
+                 source.tsx meta.var.expr.tsx meta.tag.tsx entity.name.tag.tsx support.class.component.tsx
+                             ^
+                             source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx
+                              ^^^^^^^^^^^^^^^^^^
+                              source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx entity.other.attribute-name.tsx
+                                                ^
+                                                source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx keyword.operator.assignment.tsx
+                                                 ^
+                                                 source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx string.quoted.double.tsx punctuation.definition.string.begin.tsx
+                                                  ^^^
+                                                  source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx string.quoted.double.tsx
+                                                     ^
+                                                     source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx string.quoted.double.tsx punctuation.definition.string.end.tsx
+                                                      ^
+                                                      source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx
+                                                       ^^
+                                                       source.tsx meta.var.expr.tsx meta.tag.tsx punctuation.definition.tag.end.tsx
+                                                         ^
+                                                         source.tsx punctuation.terminator.statement.tsx
+>
+ ^
+ source.tsx
+>const valid2 = <namespaced:tag namespaced:boolean-attr>foo</namespaced:tag>;
+ ^^^^^
+ source.tsx meta.var.expr.tsx storage.type.tsx
+      ^
+      source.tsx meta.var.expr.tsx
+       ^^^^^^
+       source.tsx meta.var.expr.tsx meta.var-single-variable.expr.tsx meta.definition.variable.tsx variable.other.readwrite.tsx
+             ^
+             source.tsx meta.var.expr.tsx meta.var-single-variable.expr.tsx
+              ^
+              source.tsx meta.var.expr.tsx keyword.operator.assignment.tsx
+               ^
+               source.tsx meta.var.expr.tsx
+                ^
+                source.tsx meta.var.expr.tsx meta.tag.tsx punctuation.definition.tag.begin.tsx
+                 ^^^^^^^^^^
+                 source.tsx meta.var.expr.tsx meta.tag.tsx entity.name.tag.namespace.tsx
+                           ^
+                           source.tsx meta.var.expr.tsx meta.tag.tsx punctuation.separator.namespace.tsx
+                            ^^^
+                            source.tsx meta.var.expr.tsx meta.tag.tsx entity.name.tag.tsx
+                               ^
+                               source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx
+                                ^^^^^^^^^^
+                                source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx entity.other.attribute-name.namespace.tsx
+                                          ^
+                                          source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx punctuation.separator.namespace.tsx
+                                           ^^^^^^^^^^^^
+                                           source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx entity.other.attribute-name.tsx
+                                                       ^
+                                                       source.tsx meta.var.expr.tsx meta.tag.tsx punctuation.definition.tag.end.tsx
+                                                        ^^^
+                                                        source.tsx meta.var.expr.tsx meta.tag.tsx meta.jsx.children.tsx
+                                                           ^^
+                                                           source.tsx meta.var.expr.tsx meta.tag.tsx punctuation.definition.tag.begin.tsx
+                                                             ^^^^^^^^^^
+                                                             source.tsx meta.var.expr.tsx meta.tag.tsx entity.name.tag.namespace.tsx
+                                                                       ^
+                                                                       source.tsx meta.var.expr.tsx meta.tag.tsx punctuation.separator.namespace.tsx
+                                                                        ^^^
+                                                                        source.tsx meta.var.expr.tsx meta.tag.tsx entity.name.tag.tsx
+                                                                           ^
+                                                                           source.tsx meta.var.expr.tsx meta.tag.tsx punctuation.definition.tag.end.tsx
+                                                                            ^
+                                                                            source.tsx punctuation.terminator.statement.tsx
+>
+ ^
+ source.tsx
+>const valid3 = <namespaced:Klass.comp.onent namespaced:attr="foo" />;
+ ^^^^^
+ source.tsx meta.var.expr.tsx storage.type.tsx
+      ^
+      source.tsx meta.var.expr.tsx
+       ^^^^^^
+       source.tsx meta.var.expr.tsx meta.var-single-variable.expr.tsx meta.definition.variable.tsx variable.other.readwrite.tsx
+             ^
+             source.tsx meta.var.expr.tsx meta.var-single-variable.expr.tsx
+              ^
+              source.tsx meta.var.expr.tsx keyword.operator.assignment.tsx
+               ^
+               source.tsx meta.var.expr.tsx
+                ^
+                source.tsx meta.var.expr.tsx meta.tag.tsx punctuation.definition.tag.begin.tsx
+                 ^^^^^^^^^^
+                 source.tsx meta.var.expr.tsx meta.tag.tsx entity.name.tag.namespace.tsx
+                           ^
+                           source.tsx meta.var.expr.tsx meta.tag.tsx punctuation.separator.namespace.tsx
+                            ^^^^^^^^^^^^^^^^
+                            source.tsx meta.var.expr.tsx meta.tag.tsx entity.name.tag.tsx support.class.component.tsx
+                                            ^
+                                            source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx
+                                             ^^^^^^^^^^
+                                             source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx entity.other.attribute-name.namespace.tsx
+                                                       ^
+                                                       source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx punctuation.separator.namespace.tsx
+                                                        ^^^^
+                                                        source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx entity.other.attribute-name.tsx
+                                                            ^
+                                                            source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx keyword.operator.assignment.tsx
+                                                             ^
+                                                             source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx string.quoted.double.tsx punctuation.definition.string.begin.tsx
+                                                              ^^^
+                                                              source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx string.quoted.double.tsx
+                                                                 ^
+                                                                 source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx string.quoted.double.tsx punctuation.definition.string.end.tsx
+                                                                  ^
+                                                                  source.tsx meta.var.expr.tsx meta.tag.tsx meta.tag.attributes.tsx
+                                                                   ^^
+                                                                   source.tsx meta.var.expr.tsx meta.tag.tsx punctuation.definition.tag.end.tsx
+                                                                     ^
+                                                                     source.tsx punctuation.terminator.statement.tsx
+>
+ ^
+ source.tsx
+>const invalid1 = <too:much:Namespace />;
+ ^^^^^
+ source.tsx meta.var.expr.tsx storage.type.tsx
+      ^
+      source.tsx meta.var.expr.tsx
+       ^^^^^^^^
+       source.tsx meta.var.expr.tsx meta.var-single-variable.expr.tsx meta.definition.variable.tsx variable.other.readwrite.tsx
+               ^
+               source.tsx meta.var.expr.tsx meta.var-single-variable.expr.tsx
+                ^
+                source.tsx meta.var.expr.tsx keyword.operator.assignment.tsx
+                 ^
+                 source.tsx meta.var.expr.tsx
+                  ^
+                  source.tsx meta.var.expr.tsx keyword.operator.relational.tsx
+                   ^^^
+                   source.tsx meta.var.expr.tsx variable.other.readwrite.tsx
+                      ^
+                      source.tsx meta.var.expr.tsx
+                       ^^^^
+                       source.tsx meta.var.expr.tsx variable.other.readwrite.tsx
+                           ^
+                           source.tsx meta.var.expr.tsx
+                            ^^^^^^^^^
+                            source.tsx meta.var.expr.tsx variable.other.readwrite.tsx
+                                     ^
+                                     source.tsx meta.var.expr.tsx
+                                      ^
+                                      source.tsx meta.var.expr.tsx keyword.operator.arithmetic.tsx
+                                       ^
+                                       source.tsx meta.var.expr.tsx keyword.operator.relational.tsx
+                                        ^
+                                        source.tsx punctuation.terminator.statement.tsx
+>
+ ^
+ source.tsx
+>const invalid2 = <namespaced-:Klass.Component too:much:namespace-attribute>foo</namespaced-:Klass.Component>;
+ ^^^^^
+ source.tsx meta.var.expr.tsx storage.type.tsx
+      ^
+      source.tsx meta.var.expr.tsx
+       ^^^^^^^^
+       source.tsx meta.var.expr.tsx meta.var-single-variable.expr.tsx meta.definition.variable.tsx variable.other.readwrite.tsx
+               ^
+               source.tsx meta.var.expr.tsx meta.var-single-variable.expr.tsx
+                ^
+                source.tsx meta.var.expr.tsx keyword.operator.assignment.tsx
+                 ^
+                 source.tsx meta.var.expr.tsx
+                  ^
+                  source.tsx meta.var.expr.tsx keyword.operator.relational.tsx
+                   ^^^^^^^^^^
+                   source.tsx meta.var.expr.tsx variable.other.readwrite.tsx
+                             ^
+                             source.tsx meta.var.expr.tsx keyword.operator.arithmetic.tsx
+                              ^
+                              source.tsx meta.var.expr.tsx
+                               ^^^^^
+                               source.tsx meta.var.expr.tsx variable.other.object.tsx
+                                    ^
+                                    source.tsx meta.var.expr.tsx punctuation.accessor.tsx
+                                     ^^^^^^^^^
+                                     source.tsx meta.var.expr.tsx variable.other.property.tsx
+                                              ^
+                                              source.tsx meta.var.expr.tsx
+                                               ^^^
+                                               source.tsx meta.var.expr.tsx variable.other.readwrite.tsx
+                                                  ^
+                                                  source.tsx meta.var.expr.tsx
+                                                   ^^^^
+                                                   source.tsx meta.var.expr.tsx variable.other.readwrite.tsx
+                                                       ^
+                                                       source.tsx meta.var.expr.tsx
+                                                        ^^^^^^^^^
+                                                        source.tsx meta.var.expr.tsx variable.other.readwrite.tsx
+                                                                 ^
+                                                                 source.tsx meta.var.expr.tsx keyword.operator.arithmetic.tsx
+                                                                  ^^^^^^^^^
+                                                                  source.tsx meta.var.expr.tsx variable.other.readwrite.tsx
+                                                                           ^
+                                                                           source.tsx meta.var.expr.tsx keyword.operator.relational.tsx
+                                                                            ^^^
+                                                                            source.tsx meta.var.expr.tsx variable.other.readwrite.tsx
+                                                                               ^
+                                                                               source.tsx meta.var.expr.tsx keyword.operator.relational.tsx
+                                                                                ^
+                                                                                source.tsx meta.var.expr.tsx keyword.operator.arithmetic.tsx
+                                                                                 ^^^^^^^^^^
+                                                                                 source.tsx meta.var.expr.tsx variable.other.readwrite.tsx
+                                                                                           ^
+                                                                                           source.tsx meta.var.expr.tsx keyword.operator.arithmetic.tsx
+                                                                                            ^
+                                                                                            source.tsx meta.var.expr.tsx
+                                                                                             ^^^^^
+                                                                                             source.tsx meta.var.expr.tsx variable.other.object.tsx
+                                                                                                  ^
+                                                                                                  source.tsx meta.var.expr.tsx punctuation.accessor.tsx
+                                                                                                   ^^^^^^^^^
+                                                                                                   source.tsx meta.var.expr.tsx variable.other.property.tsx
+                                                                                                            ^
+                                                                                                            source.tsx meta.var.expr.tsx keyword.operator.relational.tsx
+                                                                                                             ^
+                                                                                                             source.tsx punctuation.terminator.statement.tsx
\ No newline at end of file
diff --git a/tests/cases/pr557_namespacedJsx.tsx b/tests/cases/pr557_namespacedJsx.tsx
new file mode 100644
index 00000000..69d1dacd
--- /dev/null
+++ b/tests/cases/pr557_namespacedJsx.tsx
@@ -0,0 +1,10 @@
+// @onlyOwnGrammar - As this has jsx
+const valid1 = <standard-tag standard-attribute="foo" />;
+
+const valid2 = <namespaced:tag namespaced:boolean-attr>foo</namespaced:tag>;
+
+const valid3 = <namespaced:Klass.comp.onent namespaced:attr="foo" />;
+
+const invalid1 = <too:much:Namespace />;
+
+const invalid2 = <namespaced-:Klass.Component too:much:namespace-attribute>foo</namespaced-:Klass.Component>;
\ No newline at end of file