diff --git a/basis/bit-arrays/bit-arrays.factor b/basis/bit-arrays/bit-arrays.factor
index 17c391636f..42655aceb8 100644
--- a/basis/bit-arrays/bit-arrays.factor
+++ b/basis/bit-arrays/bit-arrays.factor
@@ -61,7 +61,7 @@ M: bit-array like drop dup bit-array? [ >bit-array ] unless ;
 M: bit-array new-sequence drop <bit-array> ;
 
 M: bit-array equal?
-    over bit-array? [ sequence= ] [ 2drop f ] if ;
+    over bit-array? [ [ underlying>> ] bi@ sequence= ] [ 2drop f ] if ;
 
 M: bit-array resize
     [ drop ] [
diff --git a/basis/bit-sets/bit-sets.factor b/basis/bit-sets/bit-sets.factor
index 0e97968965..34b7f13dc2 100644
--- a/basis/bit-sets/bit-sets.factor
+++ b/basis/bit-sets/bit-sets.factor
@@ -26,4 +26,6 @@ HINTS: bit-set-intersect bit-array bit-array ;
 
 : bit-set-diff ( seq1 seq2 -- seq ) [ bitnot bitand ] bit-set-map ;
 
-HINTS: bit-set-diff bit-array bit-array ;
\ No newline at end of file
+HINTS: bit-set-diff bit-array bit-array ;
+
+: bit-set-subset? ( seq1 seq2 -- ? ) dupd bit-set-intersect = ;
\ No newline at end of file