diff --git a/src/clj_http/multipart.clj b/src/clj_http/multipart.clj
index e4381ace..e2a701a7 100644
--- a/src/clj_http/multipart.clj
+++ b/src/clj_http/multipart.clj
@@ -144,12 +144,13 @@
 (defn create-multipart-entity
   "Takes a multipart vector of maps and creates a MultipartEntity with each
   map added as a part, depending on the type of content."
-  [multipart {:keys [mime-subtype multipart-mode multipart-charset]
+  [multipart {:keys [mime-subtype multipart-mode multipart-charset boundary]
               :or {mime-subtype "form-data"
                    multipart-mode HttpMultipartMode/STRICT}}]
   (let [mp-entity (doto (MultipartEntityBuilder/create)
                     (.setMode multipart-mode)
                     (.setMimeSubtype mime-subtype))]
+    (when boundary (.setBoundary mp-entity boundary))
     (when multipart-charset
       (.setCharset mp-entity (encoding-to-charset multipart-charset)))
     (doseq [m multipart]
diff --git a/test/clj_http/test/multipart_test.clj b/test/clj_http/test/multipart_test.clj
index 7c309cf5..439c5c4f 100644
--- a/test/clj_http/test/multipart_test.clj
+++ b/test/clj_http/test/multipart_test.clj
@@ -181,3 +181,12 @@
   (testing "charset is set if a multipart-charset is supplied"
     (let [mp-entity (create-multipart-entity [] {:multipart-charset "UTF-8"})]
       (is (= "UTF-8" (EntityUtils/getContentCharSet mp-entity))))))
+
+(deftest test-multipart-boundary
+  (testing "default random boundary is set when no custom boundary is supplied"
+    (let [mp-entity (create-multipart-entity [] {})]
+      (is (re-matches #"--.+--\r\n" (-> mp-entity .getContent slurp)))))
+
+  (testing "custom boundary is set when custom boundary is supplied"
+    (let [mp-entity (create-multipart-entity [] {:boundary "CustomMultipartBoundary"})]
+      (is (re-matches #"--CustomMultipartBoundary--\r\n" (-> mp-entity .getContent slurp))))))