diff --git a/pkgs/development/libraries/haskell/union-find/default.nix b/pkgs/development/libraries/haskell/union-find/default.nix
new file mode 100644
index 00000000000..b50713d5291
--- /dev/null
+++ b/pkgs/development/libraries/haskell/union-find/default.nix
@@ -0,0 +1,14 @@
+{ cabal, transformers }:
+
+cabal.mkDerivation (self: {
+  pname = "union-find";
+  version = "0.2";
+  sha256 = "1v7hj42j9w6jlzi56jg8rh4p58gfs1c5dx30wd1qqvn0p0mnihp6";
+  buildDepends = [ transformers ];
+  meta = {
+    homepage = "http://github.com/nominolo/union-find";
+    description = "Efficient union and equivalence testing of sets";
+    license = self.stdenv.lib.licenses.bsd3;
+    platforms = self.ghc.meta.platforms;
+  };
+})
diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index 79045f14831..ace5b0ff308 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -1990,6 +1990,8 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
 
   unboundedDelays = callPackage ../development/libraries/haskell/unbounded-delays {};
 
+  unionFind = callPackage ../development/libraries/haskell/union-find {};
+
   uniplate = callPackage ../development/libraries/haskell/uniplate {};
 
   uniqueid = callPackage ../development/libraries/haskell/uniqueid {};