diff --git a/lua/jj_mini_diff/init.lua b/lua/jj_mini_diff/init.lua
index b3f6d01..4b0336a 100644
--- a/lua/jj_mini_diff/init.lua
+++ b/lua/jj_mini_diff/init.lua
@@ -17,8 +17,16 @@ local function _run_jj_command(args)
   return output
 end
 
+-- Define Neovim signs for diff
+local function _define_signs()
+  vim.fn.sign_define("JjDiffAdd", { text = "│", texthl = "JjDiffAdd", numhl = "JjDiffAdd" })
+  vim.fn.sign_define("JjDiffChange", { text = "│", texthl = "JjDiffChange", numhl = "JjDiffChange" })
+  vim.fn.sign_define("JjDiffDelete", { text = "─", texthl = "JjDiffDelete", numhl = "JjDiffDelete" })
+end
+
 function M.setup(opts)
   opts = opts or {}
+  _define_signs() -- Call to define signs
   -- TODO: Implement configuration options
 end