diff --git a/lua/mason-registry/fourmolu/init.lua b/lua/mason-registry/fourmolu/init.lua
new file mode 100644
index 000000000..11252901e
--- /dev/null
+++ b/lua/mason-registry/fourmolu/init.lua
@@ -0,0 +1,32 @@
+local Pkg = require "mason-core.package"
+local github = require "mason-core.managers.github"
+local _ = require "mason-core.functional"
+local platform = require "mason-core.platform"
+local std = require "mason-core.managers.std"
+
+return Pkg.new {
+    name = "fourmolu",
+    desc = [[A fork of Ormolu that uses four space indentation and allows arbitrary configuration.]],
+    homepage = "https://hackage.haskell.org/package/fourmolu",
+    languages = { Pkg.Lang.Haskell },
+    categories = { Pkg.Cat.Formatter },
+    ---@async
+    ---@param ctx InstallContext
+    install = function(ctx)
+        github
+            .download_release_file({
+                repo = "fourmolu/fourmolu",
+                out_file = "fourmolu",
+                asset_file = function(version)
+                    local target = _.coalesce(
+                        _.when(platform.is.mac_x64, "fourmolu-%s-osx-x86_64"),
+                        _.when(platform.is.linux_x64_gnu, "fourmolu-%s-linux-x86_64")
+                    )
+                    return target and target:format(version:gsub("^v", ""))
+                end,
+            })
+            .with_receipt()
+        std.chmod("+x", { "fourmolu" })
+        ctx:link_bin("fourmolu", "fourmolu")
+    end,
+}
diff --git a/lua/mason-registry/index.lua b/lua/mason-registry/index.lua
index 27076e4a2..ba8234bbc 100644
--- a/lua/mason-registry/index.lua
+++ b/lua/mason-registry/index.lua
@@ -80,6 +80,7 @@ return {
   ["flux-lsp"] = "mason-registry.flux-lsp",
   ["foam-language-server"] = "mason-registry.foam-language-server",
   fortls = "mason-registry.fortls",
+  fourmolu = "mason-registry.fourmolu",
   fsautocomplete = "mason-registry.fsautocomplete",
   gersemi = "mason-registry.gersemi",
   gitlint = "mason-registry.gitlint",
diff --git a/lua/mason/mappings/language.lua b/lua/mason/mappings/language.lua
index c8d5a7ddd..d12bc7b9a 100644
--- a/lua/mason/mappings/language.lua
+++ b/lua/mason/mappings/language.lua
@@ -54,7 +54,7 @@ return {
   haml = { "haml-lint" },
   handlebargs = { "djlint" },
   handlebars = { "glint" },
-  haskell = { "haskell-language-server" },
+  haskell = { "fourmolu", "haskell-language-server" },
   haxe = { "haxe-language-server" },
   hoon = { "hoon-language-server" },
   html = { "erb-lint", "html-lsp", "prettier", "prettierd" },