diff --git a/spec/app/atom-spec.coffee b/spec/app/atom-spec.coffee
index 991916d1d..c479f58b3 100644
--- a/spec/app/atom-spec.coffee
+++ b/spec/app/atom-spec.coffee
@@ -144,6 +144,12 @@ describe "the `atom` global", ->
           expect(atom.packageStates['package-with-serialization']).toEqual someNumber: 1
           expect(console.error).toHaveBeenCalled()
 
+        it "removes the package's grammars", ->
+          atom.activatePackage('package-with-grammars')
+          atom.deactivatePackage('package-with-grammars')
+          expect(syntax.selectGrammar('a.alot').name).toBe 'Null Grammar'
+          expect(syntax.selectGrammar('a.alittle').name).toBe 'Null Grammar'
+
       describe "texmate packages", ->
         it "removes the package's grammars", ->
           expect(syntax.selectGrammar("file.rb").name).toBe "Null Grammar"
diff --git a/src/app/atom-package.coffee b/src/app/atom-package.coffee
index 75e9f52a6..dc27d70ac 100644
--- a/src/app/atom-package.coffee
+++ b/src/app/atom-package.coffee
@@ -97,6 +97,7 @@ class AtomPackage extends Package
       console.error "Error serializing package '#{@name}'", e.stack
 
   deactivate: ->
+    syntax.removeGrammar(grammar) for grammar in @grammars
     @mainModule?.deactivate?()
 
   requireMainModule: ->