diff --git a/scheme/base.sld b/scheme/base.sld
index 934fad7e..de03033a 100644
--- a/scheme/base.sld
+++ b/scheme/base.sld
@@ -174,7 +174,8 @@
       (list->vector
         (string->list str)))
     (define (vector-append . vecs)
-      vecs) ; TODO
+      (list->vector
+        (apply append (map vector->list vecs))))
 
     (define (vector-copy vec . opts)
       (letrec ((len (vector-length vec))