diff --git a/manifest.dhall b/manifest.dhall
index 0ffc3ae805087afb1a0accc4cfefe6633aa8e49f..483f01255d4315244054970a949a88d9a9d98347 100644
--- a/manifest.dhall
+++ b/manifest.dhall
@@ -102,6 +102,7 @@ in  [ callHackage "Cabal" "3.8.1.0"
         "https://github.com/NixOS/cabal2nix"
         (None Text)
         (Some "cabal2nix")
+    , callHackage "case-insensitive" "1.2.1.0"
     , callHackage "cassava" "0.5.3.0"
     , callHackage "cassava-megaparsec" "2.0.4"
     , callHackage "cereal" "0.5.8.3"
diff --git a/overlay.nix b/overlay.nix
index fc6b761ddcc0c553e4440b45c68f224fbe05b029..9f21c0fcde61ddb03a27d5a050a6d43ad5fb7022 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -79,6 +79,8 @@ final: prev: with pkgs.haskell.lib; {
 
   cabal2nix = prev.callPackage (./pkgs/cabal2nix.nix) { };
 
+  case-insensitive = prev.callPackage (./pkgs/case-insensitive.nix) { };
+
   cassava = prev.callPackage (./pkgs/cassava.nix) { };
 
   cassava-megaparsec = prev.callPackage (./pkgs/cassava-megaparsec.nix) { };
diff --git a/pkgs/case-insensitive.nix b/pkgs/case-insensitive.nix
new file mode 100644
index 0000000000000000000000000000000000000000..4a0b5f797f41e4e3c0718fbb09a2a5900ef1ad7c
--- /dev/null
+++ b/pkgs/case-insensitive.nix
@@ -0,0 +1,41 @@
+{ mkDerivation
+, base
+, bytestring
+, criterion
+, deepseq
+, hashable
+, HUnit
+, lib
+, test-framework
+, test-framework-hunit
+, text
+}:
+mkDerivation {
+  pname = "case-insensitive";
+  version = "1.2.1.0";
+  sha256 = "296dc17e0c5f3dfb3d82ced83e4c9c44c338ecde749b278b6eae512f1d04e406";
+  isLibrary = true;
+  isExecutable = false;
+  enableSeparateDataOutput = false;
+  libraryHaskellDepends = [ base bytestring deepseq hashable text ];
+  testHaskellDepends = [
+    base
+    bytestring
+    HUnit
+    test-framework
+    test-framework-hunit
+    text
+  ];
+  benchmarkHaskellDepends = [ base bytestring criterion deepseq ];
+  enableLibraryProfiling = false;
+  enableExecutableProfiling = false;
+  doHaddock = false;
+  jailbreak = true;
+  doCheck = false;
+  doBenchmark = false;
+  hyperlinkSource = false;
+  homepage = "https://github.com/basvandijk/case-insensitive";
+  description = "Case insensitive string comparison";
+  license = lib.licenses.bsd3;
+  broken = false;
+}