diff --git a/lib/typeprof/lsp.rb b/lib/typeprof/lsp.rb
index bdf55adaf..9977b4e9b 100644
--- a/lib/typeprof/lsp.rb
+++ b/lib/typeprof/lsp.rb
@@ -1,6 +1,5 @@
 require "socket"
 require "json"
-require "uri"
 
 require_relative "lsp/text"
 require_relative "lsp/messages"
diff --git a/lib/typeprof/lsp/messages.rb b/lib/typeprof/lsp/messages.rb
index 55e944412..603a497c9 100644
--- a/lib/typeprof/lsp/messages.rb
+++ b/lib/typeprof/lsp/messages.rb
@@ -72,7 +72,7 @@ class Message::Initialize < Message
     def run
       folders = @params[:workspaceFolders].map do |folder|
         folder => { uri:, }
-        URI(uri).path
+        TypeProf::LSP.file_uri_to_path(uri)
       end
 
       @server.add_workspaces(folders)
@@ -146,7 +146,7 @@ class Message::TextDocument::DidOpen < Message
     def run
       @params => { textDocument: { uri:, version:, text: } }
 
-      path = URI(uri).path
+      path = TypeProf::LSP.file_uri_to_path(uri)
       return unless @server.target_path?(path)
 
       text = Text.new(path, text, version)
diff --git a/lib/typeprof/lsp/util.rb b/lib/typeprof/lsp/util.rb
index 2cab8345c..770b6b131 100644
--- a/lib/typeprof/lsp/util.rb
+++ b/lib/typeprof/lsp/util.rb
@@ -48,4 +48,14 @@ def self.load_json_with_comments(path, **opts)
 
     JSON.parse(json, **opts)
   end
+
+  FILE_URL_PREFIX = File::ALT_SEPARATOR != "\\" ? "file://" : "file:///"
+
+  def self.file_path_to_uri(path)
+    FILE_URL_PREFIX + File.expand_path(path)
+  end
+
+  def self.file_uri_to_path(url)
+    url.delete_prefix(FILE_URL_PREFIX)
+  end
 end
diff --git a/test/lsp/lsp_test.rb b/test/lsp/lsp_test.rb
index 30b430372..1d909160e 100644
--- a/test/lsp/lsp_test.rb
+++ b/test/lsp/lsp_test.rb
@@ -39,7 +39,7 @@ def setup
     end
 
     def init(fixture)
-      @folder = "file://" + File.expand_path(File.join(__dir__, "..", "fixtures", fixture)) + "/"
+      @folder = TypeProf::LSP.file_path_to_uri(File.expand_path(File.join(__dir__, "..", "fixtures", fixture))) + "/"
       id = request("initialize", workspaceFolders: [{ uri: @folder }])
       expect_response(id) do |recv|
         assert_equal({ name: "typeprof", version: TypeProf::VERSION }, recv[:serverInfo])