diff --git a/buildtrigger/basehandler.py b/buildtrigger/basehandler.py
index a991c3be9..64647e06c 100644
--- a/buildtrigger/basehandler.py
+++ b/buildtrigger/basehandler.py
@@ -290,7 +290,10 @@ class BuildTriggerHandler(object):
   def get_dockerfile_path(self):
     """ Returns the normalized path to the Dockerfile found in the subdirectory
         in the config. """
-    return self.config.get('subdir', '')
+    dockerfile_path = self.config.get('subdir') or 'Dockerfile'
+    if dockerfile_path[0] == '/':
+      dockerfile_path = dockerfile_path[1:]
+    return dockerfile_path
 
   def prepare_build(self, metadata, is_manual=False):
     # Ensure that the metadata meets the scheme.
diff --git a/buildtrigger/githubhandler.py b/buildtrigger/githubhandler.py
index 80dd5e2aa..f6687798e 100644
--- a/buildtrigger/githubhandler.py
+++ b/buildtrigger/githubhandler.py
@@ -371,6 +371,9 @@ class GithubBuildTrigger(BuildTriggerHandler):
       raise RepositoryReadException(message)
 
     path = self.get_dockerfile_path()
+    if not path:
+      return None
+
     try:
       file_info = repo.get_file_contents(path)
     except GithubException as ghe:
diff --git a/buildtrigger/test/bitbucketmock.py b/buildtrigger/test/bitbucketmock.py
index 93d66d143..c53f4a57f 100644
--- a/buildtrigger/test/bitbucketmock.py
+++ b/buildtrigger/test/bitbucketmock.py
@@ -23,7 +23,7 @@ def get_repo_path_contents(path, revision):
   return (True, data, None)
 
 def get_raw_path_contents(path, revision):
-  if path == '/Dockerfile':
+  if path == 'Dockerfile':
     return (True, 'hello world', None)
 
   if path == 'somesubdir/Dockerfile':
diff --git a/buildtrigger/test/githubmock.py b/buildtrigger/test/githubmock.py
index 77c8a7a1f..f42ec57ca 100644
--- a/buildtrigger/test/githubmock.py
+++ b/buildtrigger/test/githubmock.py
@@ -119,7 +119,7 @@ def get_mock_github():
     return [master, otherbranch]
 
   def get_file_contents_mock(filepath):
-    if filepath == '/Dockerfile':
+    if filepath == 'Dockerfile':
       m = Mock()
       m.content = 'hello world'
       return m
diff --git a/buildtrigger/test/gitlabmock.py b/buildtrigger/test/gitlabmock.py
index 8a2212be9..c7d4a5865 100644
--- a/buildtrigger/test/gitlabmock.py
+++ b/buildtrigger/test/gitlabmock.py
@@ -151,7 +151,7 @@ def gettag_mock(repo_id, tag):
   }
 
 def getrawfile_mock(repo_id, branch_name, path):
-  if path == '/Dockerfile':
+  if path == 'Dockerfile':
     return 'hello world'
 
   if path == 'somesubdir/Dockerfile':