--- a/gfx/thebes/gfxFcPlatformFontList.cpp
+++ b/gfx/thebes/gfxFcPlatformFontList.cpp
@@ -1349,16 +1349,19 @@ gfxFcPlatformFontList::FindGenericFamily
         return genericFamily;
     }
 
     // if not found, ask fontconfig to pick the appropriate font
     nsAutoRef<FcPattern> genericPattern(FcPatternCreate());
     FcPatternAddString(genericPattern, FC_FAMILY,
                        ToFcChar8Ptr(generic.get()));
 
+    // -- prefer scalable fonts
+    FcPatternAddBool(genericPattern, FC_SCALABLE, FcTrue);
+
     // -- add the lang to the pattern
     if (!fcLang.IsEmpty()) {
         FcPatternAddString(genericPattern, FC_LANG,
                            ToFcChar8Ptr(fcLang.get()));
     }
 
     // -- perform substitutions
     FcConfigSubstitute(nullptr, genericPattern, FcMatchPattern);