diff --git a/profiles/base/use.stable.mask b/profiles/base/use.stable.mask
index ed8f342701459..d51b0e1454b67 100644
--- a/profiles/base/use.stable.mask
+++ b/profiles/base/use.stable.mask
@@ -17,6 +17,7 @@ llvm_slot_21
 # Hans de Graaff <graaff@gentoo.org> (2024-12-26)
 # Currently in testing and not ready to go stable yet.
 ruby_targets_ruby34
+ruby_targets_ruby40
 
 # Michał Górny <mgorny@gentoo.org> (2024-05-08)
 # Python implementations without stable keywords.
diff --git a/profiles/desc/ruby_targets.desc b/profiles/desc/ruby_targets.desc
index 90c5514faff65..4f98340883f12 100644
--- a/profiles/desc/ruby_targets.desc
+++ b/profiles/desc/ruby_targets.desc
@@ -1,4 +1,4 @@
-# Copyright 1999-2024 Gentoo Authors
+# Copyright 1999-2025 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 # This file contains descriptions of RUBY_TARGETS USE_EXPAND flags.
@@ -8,3 +8,4 @@ ruby31 - Build with MRI Ruby 3.1.x
 ruby32 - Build with MRI Ruby 3.2.x
 ruby33 - Build with MRI Ruby 3.3.x
 ruby34 - Build with MRI Ruby 3.4.x
+ruby40 - Build with MRI Ruby 4.0.x