diff --git a/horizon.dhall b/horizon.dhall
index 0a054c2213ed6f5c6f43747d6ec81450c0d5fefb..3e8bffe66ad67b544c2033a12a00f472b6e6ecc2 100644
--- a/horizon.dhall
+++ b/horizon.dhall
@@ -651,6 +651,7 @@ in  H.HorizonExport.MakePackageSet
           , H.callHackage "refined" "0.8"
           , H.callHackage "reflection" "2.1.6"
           , H.callHackage "relude" "1.1.0.0"
+          , H.callHackage "replace-megaparsec" "1.4.5.0"
           , H.callHackage "repline" "0.4.2.0"
           , H.callHackage "rerebase" "1.15.0.3"
           , H.callHackage "rere" "0.2"
diff --git a/initial-packages.nix b/initial-packages.nix
index 1a346cd70c5795917da03ab11c9d507dde3e7a30..3b341730667756cce9db7e7463ad598798d93ff7 100644
--- a/initial-packages.nix
+++ b/initial-packages.nix
@@ -1051,6 +1051,8 @@ self: with pkgs.haskell.lib; {
 
   relude = self.callPackage (./pkgs/relude.nix) { };
 
+  replace-megaparsec = self.callPackage (./pkgs/replace-megaparsec.nix) { };
+
   repline = self.callPackage (./pkgs/repline.nix) { };
 
   rere = self.callPackage (./pkgs/rere.nix) { };
diff --git a/pkgs/replace-megaparsec.nix b/pkgs/replace-megaparsec.nix
new file mode 100644
index 0000000000000000000000000000000000000000..63a9d9769c9c3ead3da39cb140c62575999b0599
--- /dev/null
+++ b/pkgs/replace-megaparsec.nix
@@ -0,0 +1,36 @@
+{ mkDerivation
+, Cabal
+, base
+, bytestring
+, lib
+, megaparsec
+, parser-combinators
+, text
+}:
+mkDerivation {
+  pname = "replace-megaparsec";
+  version = "1.4.5.0";
+  sha256 = "8ffa015a2421b7aa880866bc45a7350f134cc6edb865f9ff62af9706039a31d9";
+  isLibrary = true;
+  isExecutable = false;
+  enableSeparateDataOutput = false;
+  libraryHaskellDepends = [
+    base
+    bytestring
+    megaparsec
+    parser-combinators
+    text
+  ];
+  testHaskellDepends = [ base bytestring Cabal megaparsec text ];
+  enableLibraryProfiling = true;
+  enableExecutableProfiling = true;
+  doHaddock = false;
+  jailbreak = true;
+  doCheck = false;
+  doBenchmark = false;
+  hyperlinkSource = false;
+  homepage = "https://github.com/jamesdbrock/replace-megaparsec";
+  description = "Find, replace, and split string patterns with Megaparsec parsers (instead of regex)";
+  license = lib.licenses.bsd2;
+  broken = false;
+}