diff --git a/lib/xcodeproj/config.rb b/lib/xcodeproj/config.rb
index 35d48d39..e022602e 100644
--- a/lib/xcodeproj/config.rb
+++ b/lib/xcodeproj/config.rb
@@ -341,7 +341,7 @@ def strip_comment(line)
     # @return [Nil] if no include was found in the line.
     #
     def extract_include(line)
-      regexp = /#include\s*"(.+)"/
+      regexp = /#include\??\s*"(.+)"/
       match = line.match(regexp)
       match[1] if match
     end
diff --git a/spec/config_spec.rb b/spec/config_spec.rb
index 5cd511ac..f23e3210 100644
--- a/spec/config_spec.rb
+++ b/spec/config_spec.rb
@@ -229,6 +229,12 @@ def filename.open(mode)
       config.includes.first.should.be.equal 'Somefile.xcconfig'
     end
 
+    it 'contains file path refs to optional included xcconfigs' do
+      config = Xcodeproj::Config.new(fixture_path('optional-include.xcconfig'))
+      config.includes.size.should.be.equal 1
+      config.includes.first.should.be.equal 'Optional.xcconfig'
+    end
+
     it 'contains file path refs to all included xcconfigs, even without the extension added' do
       config = Xcodeproj::Config.new(fixture_path('config-with-include-no-extension.xcconfig'))
       config.includes.size.should.be.equal 1
diff --git a/spec/fixtures/optional-include.xcconfig b/spec/fixtures/optional-include.xcconfig
new file mode 100644
index 00000000..352e589e
--- /dev/null
+++ b/spec/fixtures/optional-include.xcconfig
@@ -0,0 +1 @@
+#include? "Optional.xcconfig"