diff --git a/youtube_dl/extractor/lynda.py b/youtube_dl/extractor/lynda.py
index 18efe5a094..a00f6e5e5e 100644
--- a/youtube_dl/extractor/lynda.py
+++ b/youtube_dl/extractor/lynda.py
@@ -30,8 +30,8 @@ def _login(self):
             return
 
         login_form = {
-            'username': username,
-            'password': password,
+            'username': username.encode('utf-8'),
+            'password': password.encode('utf-8'),
             'remember': 'false',
             'stayPut': 'false'
         }