diff --git a/src/datatrove/pipeline/filters/gopher_quality_filter.py b/src/datatrove/pipeline/filters/gopher_quality_filter.py
index 9e5e68b6..4dc33384 100644
--- a/src/datatrove/pipeline/filters/gopher_quality_filter.py
+++ b/src/datatrove/pipeline/filters/gopher_quality_filter.py
@@ -119,7 +119,7 @@ def filter(self, doc: Document) -> bool | tuple[bool, str]:
             return False, "gopher_below_alpha_threshold"
 
         # stop word filter
-        if self.min_stop_words and sum(w in self.stop_words for w in words) < self.min_stop_words:
+        if self.min_stop_words and len(self.stop_words.intersection(set(words))) < self.min_stop_words:
             return False, "gopher_enough_stop_words"
 
         return True