diff --git a/pkgs/servers/firebird/default.nix b/pkgs/servers/firebird/default.nix
index 1612f518a7953..dca4bf5146d18 100644
--- a/pkgs/servers/firebird/default.nix
+++ b/pkgs/servers/firebird/default.nix
@@ -55,34 +55,6 @@ let
   };
 in
 rec {
-
-  firebird_2_5 = stdenv.mkDerivation (
-    base
-    // rec {
-      version = "2.5.9";
-
-      src = fetchFromGitHub {
-        owner = "FirebirdSQL";
-        repo = "firebird";
-        rev = "R${builtins.replaceStrings [ "." ] [ "_" ] version}";
-        sha256 = "sha256-YyvlMeBux80OpVhsCv+6IVxKXFRsgdr+1siupMR13JM=";
-      };
-
-      configureFlags = base.configureFlags ++ [ "--with-system-icu" ];
-
-      installPhase = ''
-        runHook preInstall
-        mkdir -p $out
-        cp -r gen/firebird/* $out
-        runHook postInstall
-      '';
-
-      meta = base.meta // {
-        platforms = [ "x86_64-linux" ];
-      };
-    }
-  );
-
   firebird_3 = stdenv.mkDerivation (
     base
     // rec {
diff --git a/pkgs/top-level/aliases.nix b/pkgs/top-level/aliases.nix
index 2ec2150659427..4774e9ae1cd95 100644
--- a/pkgs/top-level/aliases.nix
+++ b/pkgs/top-level/aliases.nix
@@ -668,6 +668,7 @@ mapAliases {
   finger_bsd = bsd-finger;
   fingerd_bsd = bsd-fingerd;
   fira-code-nerdfont = lib.warnOnInstantiate "fira-code-nerdfont is redundant. Use nerd-fonts.fira-code instead." nerd-fonts.fira-code; # Added 2024-11-10
+  firebird_2_5 = throw "'firebird_2_5' has been removed as it has reached end-of-life and does not build."; # Added 2025-06-10
   firefox-esr-115 = throw "The Firefox 115 ESR series has reached its end of life. Upgrade to `firefox-esr` or `firefox-esr-128` instead.";
   firefox-esr-115-unwrapped = throw "The Firefox 115 ESR series has reached its end of life. Upgrade to `firefox-esr-unwrapped` or `firefox-esr-128-unwrapped` instead.";
   firefox-wayland = firefox; # Added 2022-11-15
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 43a4155249883..0906afb6dcee0 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -10321,7 +10321,6 @@ with pkgs;
   inherit (callPackages ../servers/firebird { })
     firebird_4
     firebird_3
-    firebird_2_5
     firebird
     ;