diff --git a/lib/mock_redis/list_methods.rb b/lib/mock_redis/list_methods.rb
index 412bbdf..9155a6c 100644
--- a/lib/mock_redis/list_methods.rb
+++ b/lib/mock_redis/list_methods.rb
@@ -97,7 +97,7 @@ def lmpop(*keys, **options)
         assert_listy(key)
       end
 
-      modifier = options.is_a?(Hash) && options[:timeout]&.to_s&.downcase || 'left'
+      modifier = options.is_a?(Hash) && options[:modifier]&.to_s&.downcase || 'left'
       count = (options.is_a?(Hash) && options[:count]) || 1
 
       unless %w[left right].include?(modifier)