diff --git a/lib/main.js b/lib/main.js
index 43711f39..42c8196a 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -91,9 +91,7 @@ function config (options /*: ?DotenvConfigOptions */) /*: DotenvConfigOutput */
     if (options.encoding != null) {
       encoding = options.encoding
     }
-    if (options.debug != null) {
-      debug = true
-    }
+    debug = Boolean(options.debug)
   }
 
   try {