diff --git a/guix/build/ruby-build-system.scm b/guix/build/ruby-build-system.scm
index d78986da10..09ae2390a5 100644
--- a/guix/build/ruby-build-system.scm
+++ b/guix/build/ruby-build-system.scm
@@ -24,6 +24,7 @@
   #:use-module (ice-9 ftw)
   #:use-module (ice-9 match)
   #:use-module (ice-9 popen)
+  #:use-module (ice-9 rdelim)
   #:use-module (ice-9 regex)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)