diff --git a/pkgs/development/interpreters/ruby/default.nix b/pkgs/development/interpreters/ruby/default.nix
index 7b36b04d114..189be8945fa 100644
--- a/pkgs/development/interpreters/ruby/default.nix
+++ b/pkgs/development/interpreters/ruby/default.nix
@@ -108,6 +108,9 @@ let
           sed -i configure.ac -e '/config.guess/d'
           cp --remove-destination ${config}/config.guess tool/
           cp --remove-destination ${config}/config.sub tool/
+          # Make the build reproducible for ruby <= 2.7
+          # See https://github.com/ruby/io-console/commit/679a941d05d869f5e575730f6581c027203b7b26#diff-d8422f096931c58d4463e2489f62a228b0f24f0492950ba88c8c89a0d741cfe6
+          sed -i ext/io/console/io-console.gemspec -e '/s\.date/d'
         '';
 
         # Force the revision.h generation. Somehow `revision.tmp` is an empty
diff --git a/pkgs/development/ruby-modules/gem/default.nix b/pkgs/development/ruby-modules/gem/default.nix
index 158d5891ec3..910949d847c 100644
--- a/pkgs/development/ruby-modules/gem/default.nix
+++ b/pkgs/development/ruby-modules/gem/default.nix
@@ -207,7 +207,7 @@ stdenv.mkDerivation ((builtins.removeAttrs attrs ["source"]) // {
     # looks like useless files which break build repeatability and consume space
     pushd $out/${ruby.gemPath}
     rm -fv doc/*/*/created.rid || true
-    rm -fv {gems/*/ext/*,extensions/*/*/*}/{mkmf.log,gem_make.out} || true
+    rm -fv {gems/*/ext/*,extensions/*/*/*}/{Makefile,mkmf.log,gem_make.out} || true
     rm -fvr cache
     popd