diff --git a/guix/build-system/ocaml.scm b/guix/build-system/ocaml.scm
index 4cd7dba3d8e..c2b79af9bc6 100644
--- a/guix/build-system/ocaml.scm
+++ b/guix/build-system/ocaml.scm
@@ -123,6 +123,14 @@
 (define (default-ocaml5.3-dune)
   (@* (gnu packages ocaml) ocaml5.3-dune))
 
+;; The default versions of core packages within the 5.x series.
+
+(define default-ocaml5 default-ocaml5.3)
+
+(define default-ocaml5-findlib default-ocaml5.3-findlib)
+
+(define default-ocaml5-dune default-ocaml5.3-dune)
+
 (define* (package-with-explicit-ocaml ocaml findlib dune old-prefix new-prefix
                                        #:key variant-property)
   "Return a procedure of one argument, P.  The procedure creates a package