diff --git a/lib/github-file.coffee b/lib/github-file.coffee
index 116a897..20bf9d1 100644
--- a/lib/github-file.coffee
+++ b/lib/github-file.coffee
@@ -79,8 +79,8 @@ class GitHubFile
   openRepository: ->
     @isOpenable().then (isOpenable) =>
       if isOpenable
-        @gitHubRepoUrl().then (gitHubRepoUrl) =>
-          @openUrlInBrowser(gitHubRepoUrl)
+        @treeUrl().then (treeUrl) =>
+          @openUrlInBrowser(treeUrl)
       else
         @reportValidationErrors()
 
@@ -170,6 +170,14 @@ class GitHubFile
       .then ([gitHubRepoUrl, branchName]) =>
         "#{gitHubRepoUrl}/compare/#{@encodeSegments(branchName)}"
 
+  treeUrl: ->
+    Promise.all([@gitHubRepoUrl(), @remoteBranchName()])
+      .then ([gitHubRepoUrl, remoteBranchName]) ->
+        if remoteBranchName isnt 'master'
+          "#{gitHubRepoUrl}/tree/#{remoteBranchName}"
+        else
+          gitHubRepoUrl
+
   encodeSegments: (segments='') ->
     segments = segments.split('/')
     segments = segments.map (segment) -> encodeURIComponent(segment)
diff --git a/spec/fixtures/some-branch.git/HEAD b/spec/fixtures/some-branch.git/HEAD
new file mode 100644
index 0000000..37c771a
--- /dev/null
+++ b/spec/fixtures/some-branch.git/HEAD
@@ -0,0 +1 @@
+ref: refs/heads/some-branch
diff --git a/spec/fixtures/some-branch.git/config b/spec/fixtures/some-branch.git/config
new file mode 100644
index 0000000..0ce88ff
--- /dev/null
+++ b/spec/fixtures/some-branch.git/config
@@ -0,0 +1,13 @@
+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = false
+	logallrefupdates = true
+	ignorecase = true
+	precomposeunicode = false
+[remote "origin"]
+	url = https://github.com/some-user/some-repo.git
+	fetch = +refs/heads/*:refs/remotes/origin/*
+[branch "some-branch"]
+	remote = origin
+	merge = refs/heads/some-branch
diff --git a/spec/fixtures/some-branch.git/index b/spec/fixtures/some-branch.git/index
new file mode 100644
index 0000000..ac609f4
Binary files /dev/null and b/spec/fixtures/some-branch.git/index differ
diff --git a/spec/fixtures/some-branch.git/objects/5c/dc5a2508dfc832223df221a8e55fb6ccf95932 b/spec/fixtures/some-branch.git/objects/5c/dc5a2508dfc832223df221a8e55fb6ccf95932
new file mode 100644
index 0000000..1a76bd5
Binary files /dev/null and b/spec/fixtures/some-branch.git/objects/5c/dc5a2508dfc832223df221a8e55fb6ccf95932 differ
diff --git a/spec/fixtures/some-branch.git/objects/80/b7897ceb6bd7531708509b50afeab36a4b73fd b/spec/fixtures/some-branch.git/objects/80/b7897ceb6bd7531708509b50afeab36a4b73fd
new file mode 100644
index 0000000..1d0efa7
--- /dev/null
+++ b/spec/fixtures/some-branch.git/objects/80/b7897ceb6bd7531708509b50afeab36a4b73fd
@@ -0,0 +1 @@
+x
��A�0@Q�=�\@S��	1nu�
ʴ�5@
��ܾ��\��4�d���G�6$�MH����(
-sr�*�J������XC��g����O�O\�4��\g\Kp�g�զ�X�	u��?��R_�@�
\ No newline at end of file
diff --git a/spec/fixtures/some-branch.git/objects/98/4f6dfa5e1ac016cb4e4d11f39343efb3c27d7f b/spec/fixtures/some-branch.git/objects/98/4f6dfa5e1ac016cb4e4d11f39343efb3c27d7f
new file mode 100644
index 0000000..f9c9b28
Binary files /dev/null and b/spec/fixtures/some-branch.git/objects/98/4f6dfa5e1ac016cb4e4d11f39343efb3c27d7f differ
diff --git a/spec/fixtures/some-branch.git/objects/bf/b04df9a5bf7ad257575599558b54b3fc335f24 b/spec/fixtures/some-branch.git/objects/bf/b04df9a5bf7ad257575599558b54b3fc335f24
new file mode 100644
index 0000000..53983f2
Binary files /dev/null and b/spec/fixtures/some-branch.git/objects/bf/b04df9a5bf7ad257575599558b54b3fc335f24 differ
diff --git a/spec/fixtures/some-branch.git/refs/heads/some-branch b/spec/fixtures/some-branch.git/refs/heads/some-branch
new file mode 100644
index 0000000..5358190
--- /dev/null
+++ b/spec/fixtures/some-branch.git/refs/heads/some-branch
@@ -0,0 +1 @@
+80b7897ceb6bd7531708509b50afeab36a4b73fd
diff --git a/spec/github-file-spec.coffee b/spec/github-file-spec.coffee
index 76cfa53..f044b42 100644
--- a/spec/github-file-spec.coffee
+++ b/spec/github-file-spec.coffee
@@ -375,6 +375,38 @@ describe "GitHubFile", ->
           runs -> expect(githubFile.openUrlInBrowser).toHaveBeenCalledWith \
             'https://github.com/some-user/some-repo'
 
+      describe "when the branch is not master", ->
+        fixtureName = 'some-branch'
+
+        beforeEach ->
+          setupWorkingDir(fixtureName)
+          setupGithubFile()
+
+        afterEach ->
+          teardownWorkingDirAndRestoreFixture(fixtureName)
+
+        it "opens the GitHub.com tree URL for the branch", ->
+          spyOn(githubFile, 'openUrlInBrowser')
+          waitsForPromise -> githubFile.openRepository()
+          runs -> expect(githubFile.openUrlInBrowser).toHaveBeenCalledWith \
+            'https://github.com/some-user/some-repo/tree/some-branch'
+
+      describe "when the local branch is not tracked", ->
+        fixtureName = 'non-tracked-branch'
+
+        beforeEach ->
+          setupWorkingDir(fixtureName)
+          setupGithubFile()
+
+        afterEach ->
+          teardownWorkingDirAndRestoreFixture(fixtureName)
+
+        it "opens the GitHub.com reposiotry URL", ->
+          spyOn(githubFile, 'openUrlInBrowser')
+          waitsForPromise -> githubFile.openRepository()
+          runs -> expect(githubFile.openUrlInBrowser).toHaveBeenCalledWith \
+            'https://github.com/some-user/some-repo'
+
     describe "openIssues", ->
       describe 'when the file is openable on GitHub.com', ->
         fixtureName = 'github-remote'