diff --git a/pkgs/development/interpreters/ruby/default.nix b/pkgs/development/interpreters/ruby/default.nix
index 57217b0550ce..15a90e41c5e4 100644
--- a/pkgs/development/interpreters/ruby/default.nix
+++ b/pkgs/development/interpreters/ruby/default.nix
@@ -412,9 +412,9 @@ in
     cargoHash = "sha256-5Tp8Kth0yO89/LIcU8K01z6DdZRr8MAA0DPKqDEjIt0=";
   };
 
-  ruby_3_5 = generic {
-    version = rubyVersion "3" "5" "0" "preview1";
-    hash = "sha256-7PCcfrkC6Rza+cxVPNAMypuEiz/A4UKXhQ+asIzdRvA=";
+  ruby_4_0 = generic {
+    version = rubyVersion "4" "0" "0" "preview3";
+    hash = "sha256-Q9CSbndvvVWZrcx7zLTMyAThCfQCogaGB6KoZWLCzcA=";
     cargoHash = "sha256-z7NwWc4TaR042hNx0xgRkh/BQEpEJtE53cfrN0qNiE0=";
   };
 
diff --git a/pkgs/top-level/aliases.nix b/pkgs/top-level/aliases.nix
index d03a80ed8074..77c37bbad131 100644
--- a/pkgs/top-level/aliases.nix
+++ b/pkgs/top-level/aliases.nix
@@ -1445,8 +1445,10 @@ mapAliases {
   ruby-zoom = throw "'ruby-zoom' has been removed due to lack of maintaince and had not been updated since 2020"; # Added 2025-08-24
   ruby_3_1 = throw "ruby_3_1 has been removed, as it is has reached end‐of‐life upstream"; # Added 2025-10-12
   ruby_3_2 = throw "ruby_3_2 has been removed, as it will reach end‐of‐life upstream during Nixpkgs 25.11’s support cycle"; # Added 2025-10-12
+  ruby_3_5 = ruby_4_0; # Added 2025-12-22
   rubyPackages_3_1 = throw "rubyPackages_3_1 has been removed, as it is has reached end‐of‐life upstream"; # Added 2025-10-12
-  rubyPackages_3_2 = throw "rubyPackages_3_2 has been removed, as it will reach end‐of‐life upstream during Nixpkgs 25.11’s support cycle"; # Added 2025-10-12
+  rubyPackages_3_2 = throw "rubyPackages_3_2 has been removed, as it will reach end‐of‐life upstream during Nixpkgs 25.11's support cycle"; # Added 2025-10-12
+  rubyPackages_3_5 = rubyPackages_4_0; # Added 2025-12-22
   rucksack = throw "rucksack was removed due to numerous vulnerabilities in freeimage"; # Added 2025-10-23
   runCommandNoCC = warnAlias "'runCommandNoCC' has been renamed to/replaced by 'runCommand'" runCommand; # Converted to warning 2025-10-28
   runCommandNoCCLocal = warnAlias "'runCommandNoCCLocal' has been renamed to/replaced by 'runCommandLocal'" runCommandLocal; # Converted to warning 2025-10-28
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 1ce0720b47d2..0efb0415f1a7 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -5740,7 +5740,7 @@ with pkgs;
     mkRuby
     ruby_3_3
     ruby_3_4
-    ruby_3_5
+    ruby_4_0
     ;
 
   ruby = ruby_3_3;
@@ -5748,7 +5748,7 @@ with pkgs;
 
   rubyPackages_3_3 = recurseIntoAttrs ruby_3_3.gems;
   rubyPackages_3_4 = recurseIntoAttrs ruby_3_4.gems;
-  rubyPackages_3_5 = recurseIntoAttrs ruby_3_5.gems;
+  rubyPackages_4_0 = recurseIntoAttrs ruby_4_0.gems;
 
   inherit (callPackages ../applications/networking/cluster/spark { })
     spark_4_0