diff --git a/grammars.yml b/grammars.yml
index 38caeb4f..4bd66f12 100644
--- a/grammars.yml
+++ b/grammars.yml
@@ -178,6 +178,8 @@ vendor/grammars/assembly.tmbundle:
 - source.x86asm
 vendor/grammars/atom-fsharp/:
 - source.fsharp
+- source.fsharp.fsi
+- source.fsharp.fsx
 vendor/grammars/atom-language-purescript/:
 - source.purescript
 vendor/grammars/atom-salt: