diff --git a/lib/jekyll.rb b/lib/jekyll.rb
index 493b8562..6e489264 100644
--- a/lib/jekyll.rb
+++ b/lib/jekyll.rb
@@ -129,8 +129,10 @@ module Jekyll
     # then, we need to know where to look for _config.yml
     source = override['source'] || Jekyll::DEFAULTS['source']
 
-    # Get configuration from <source>/_config.yml
-    config_file = File.join(source, '_config.yml')
+    # Get configuration from <source>/_config.yml or <source>/<config_file>
+    config_file = override.delete('config')
+    config_file = File.join(source, "_config.yml") if config_file.to_s.empty?
+
     begin
       config = YAML.safe_load_file(config_file)
       raise "Configuration file: (INVALID) #{config_file}" if !config.is_a?(Hash)