diff --git a/pkgs/development/interpreters/ruby/default.nix b/pkgs/development/interpreters/ruby/default.nix
index a0c563e3fb2..21a4433c9eb 100644
--- a/pkgs/development/interpreters/ruby/default.nix
+++ b/pkgs/development/interpreters/ruby/default.nix
@@ -73,7 +73,7 @@ let
             unpackdir rubySrc;
 
         # Have `configure' avoid `/usr/bin/nroff' in non-chroot builds.
-        NROFF = "${groff}/bin/nroff";
+        NROFF = if docSupport then "${groff}/bin/nroff" else null;
 
         nativeBuildInputs =
              ops useRailsExpress [ autoreconfHook bison ]