diff --git a/lua/custom/init.lua b/lua/custom/init.lua
index 23848ff..2e82000 100644
--- a/lua/custom/init.lua
+++ b/lua/custom/init.lua
@@ -193,3 +193,4 @@ end
 
 -- alias filetypes
 vim.filetype.add { extension = { tera = "html" } }
+vim.filetype.add { extension = { plaintex = "tex" } }