diff --git a/lua/neotest/consumers/diagnostic.lua b/lua/neotest/consumers/diagnostic.lua
index d442ee0..9e5c42d 100644
--- a/lua/neotest/consumers/diagnostic.lua
+++ b/lua/neotest/consumers/diagnostic.lua
@@ -55,6 +55,7 @@ local function init(client)
     logger.debug("Setting diagnostics for", self.file_path, diagnostics)
 
     vim.schedule(function()
+      if not vim.api.nvim_buf_is_valid(self.bufnr) then return end
       diag.set(diag_namespace, self.bufnr, diagnostics)
     end)
   end