diff --git a/pkgs/development/tools/parsing/bison/bison-2.3.nix b/pkgs/development/tools/parsing/bison/bison-2.3.nix
deleted file mode 100644
index fcf4ed107959..000000000000
--- a/pkgs/development/tools/parsing/bison/bison-2.3.nix
+++ /dev/null
@@ -1,38 +0,0 @@
-{stdenv, fetchurl, m4}:
-
-assert m4 != null;
-
-stdenv.mkDerivation {
-  name = "bison-2.3";
-  src = fetchurl {
-    url = mirror://gnu/bison/bison-2.3.tar.bz2;
-    md5 = "c18640c6ec31a169d351e3117ecce3ec";
-  };
-
-  buildNativeInputs = [m4];
-  propagatedBuildInputs = [m4];
-
-  meta = {
-    description = "GNU Bison, a Yacc-compatible parser generator";
-
-    longDescription = ''
-      Bison is a general-purpose parser generator that converts an
-      annotated context-free grammar into an LALR(1) or GLR parser for
-      that grammar.  Once you are proficient with Bison, you can use
-      it to develop a wide range of language parsers, from those used
-      in simple desk calculators to complex programming languages.
-
-      Bison is upward compatible with Yacc: all properly-written Yacc
-      grammars ought to work with Bison with no change.  Anyone
-      familiar with Yacc should be able to use Bison with little
-      trouble.  You need to be fluent in C or C++ programming in order
-      to use Bison.
-    '';
-
-    homepage = http://www.gnu.org/software/bison/;
-
-    license = "GPLv2+";
-  };
- 
-  passthru = { glrSupport = true; };
-}
diff --git a/pkgs/development/tools/parsing/bison/bison-2.4.nix b/pkgs/development/tools/parsing/bison/bison-2.4.nix
deleted file mode 100644
index a79a5e96381e..000000000000
--- a/pkgs/development/tools/parsing/bison/bison-2.4.nix
+++ /dev/null
@@ -1,40 +0,0 @@
-{stdenv, fetchurl, m4}:
-
-stdenv.mkDerivation rec {
-  name = "bison-2.4.3";
-
-  src = fetchurl {
-    url = "mirror://gnu/bison/${name}.tar.bz2";
-    sha256 = "019s3pdzggb71g7p7dgajhh53gh0h6nfl4yrzrs0jzsc37ph4lwk";
-  };
-
-  buildNativeInputs = [m4];
-
-  doCheck = true;
-
-  meta = {
-    description = "GNU Bison, a Yacc-compatible parser generator";
-
-    longDescription = ''
-      Bison is a general-purpose parser generator that converts an
-      annotated context-free grammar into an LALR(1) or GLR parser for
-      that grammar.  Once you are proficient with Bison, you can use
-      it to develop a wide range of language parsers, from those used
-      in simple desk calculators to complex programming languages.
-
-      Bison is upward compatible with Yacc: all properly-written Yacc
-      grammars ought to work with Bison with no change.  Anyone
-      familiar with Yacc should be able to use Bison with little
-      trouble.  You need to be fluent in C or C++ programming in order
-      to use Bison.
-    '';
-
-    homepage = http://www.gnu.org/software/bison/;
-
-    license = "GPLv3+";
-
-    maintainers = [ stdenv.lib.maintainers.ludo ];
-  };
-
-  passthru = { glrSupport = true; };
-}
diff --git a/pkgs/development/tools/parsing/bison/bison-2.5.nix b/pkgs/development/tools/parsing/bison/bison-2.5.nix
deleted file mode 100644
index ea50b8590204..000000000000
--- a/pkgs/development/tools/parsing/bison/bison-2.5.nix
+++ /dev/null
@@ -1,44 +0,0 @@
-{ stdenv, fetchurl, m4, perl }:
-
-stdenv.mkDerivation rec {
-  name = "bison-2.5";
-
-  src = fetchurl {
-    url = "mirror://gnu/bison/${name}.tar.bz2";
-    sha256 = "1f1rai3v6k6xjii94964iq0alhc2hxwapqa363nfj8rbxvv0sdqa";
-  };
-
-  buildNativeInputs = [ m4 ]
-    ++ stdenv.lib.optional doCheck perl;
-  propagatedBuildInputs = [ m4 ];
-
-  M4 = "${m4}/bin/m4";
-
-  doCheck = true;
-
-  meta = {
-    description = "GNU Bison, a Yacc-compatible parser generator";
-
-    longDescription = ''
-      Bison is a general-purpose parser generator that converts an
-      annotated context-free grammar into an LALR(1) or GLR parser for
-      that grammar.  Once you are proficient with Bison, you can use
-      it to develop a wide range of language parsers, from those used
-      in simple desk calculators to complex programming languages.
-
-      Bison is upward compatible with Yacc: all properly-written Yacc
-      grammars ought to work with Bison with no change.  Anyone
-      familiar with Yacc should be able to use Bison with little
-      trouble.  You need to be fluent in C or C++ programming in order
-      to use Bison.
-    '';
-
-    homepage = http://www.gnu.org/software/bison/;
-
-    license = "GPLv3+";
-
-    maintainers = [ stdenv.lib.maintainers.ludo ];
-  };
-
-  passthru = { glrSupport = true; };
-}
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index b821e3a6ee5d..c7f637486589 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -2950,13 +2950,6 @@ let
 
   bison1875 = callPackage ../development/tools/parsing/bison/bison-1.875.nix { };
 
-  # These attributes are unused and should be removed as well as the
-  # corresponding nix files:
-  #
-  # bison23 = callPackage ../development/tools/parsing/bison/bison-2.3.nix { };
-  # bison24 = callPackage ../development/tools/parsing/bison/bison-2.4.nix { };
-  # bison25 = callPackage ../development/tools/parsing/bison/bison-2.5.nix { };
-
   bison26 = callPackage ../development/tools/parsing/bison/bison-2.6.nix { };
 
   buildbot = callPackage ../development/tools/build-managers/buildbot {