diff --git a/frontend/src/app/dashboard/translate/GlossarySelector.tsx b/frontend/src/app/dashboard/translate/GlossarySelector.tsx
index 5dba7c5..3bffa45 100644
--- a/frontend/src/app/dashboard/translate/GlossarySelector.tsx
+++ b/frontend/src/app/dashboard/translate/GlossarySelector.tsx
@@ -284,10 +284,13 @@ export function GlossarySelector({ sourceLang, targetLang, isPro, mode, glossary
               setIsGlossaryEnabled(nextVal);
               if (!nextVal) {
                 onChange(null);
-              } else if (filteredGlossaries.length > 0 && !glossaryId) {
-                // Prefer glossary matching target language, fall back to first
+              } else if (!glossaryId) {
+                // Only auto-select if a glossary matches BOTH source and target language
                 const matching = filteredGlossaries.find(g => g.target_language === targetLang);
-                onChange(matching ? matching.id : filteredGlossaries[0].id);
+                if (matching) {
+                  onChange(matching.id);
+                }
+                // If no glossary matches the target, leave unselected — user picks manually
               }
             }}
             className={cn(