diff --git a/corpus/create_function/general.txt b/corpus/create_function/general.txt
index fdca2b4..43f2beb 100644
--- a/corpus/create_function/general.txt
+++ b/corpus/create_function/general.txt
@@ -123,3 +123,37 @@ CREATE FUNCTION FOO () RETURNS TABLE(a text, b bigint) AS 'select' LANGUAGE sql;
           (identifier))))
     (string)
     (identifier)))
+
+================================================================================
+security definer
+================================================================================
+CREATE FUNCTION FOO () RETURNS void AS 'select' LANGUAGE sql SECURITY definer;
+--------------------------------------------------------------------------------
+
+(source_file
+  (create_function_statement
+    (function_signature
+      (identifier)
+      (function_parameters))
+    (function_return
+      (identifier))
+    (string)
+    (identifier)
+    (function_run_as)))
+
+================================================================================
+security invoker
+================================================================================
+CREATE FUNCTION FOO () RETURNS void AS 'select' LANGUAGE sql SECURITY INVOKER;
+--------------------------------------------------------------------------------
+
+(source_file
+  (create_function_statement
+    (function_signature
+      (identifier)
+      (function_parameters))
+    (function_return
+      (identifier))
+    (string)
+    (identifier)
+    (function_run_as)))
diff --git a/grammar.js b/grammar.js
index e77c75d..c6530cc 100644
--- a/grammar.js
+++ b/grammar.js
@@ -582,7 +582,13 @@ module.exports = grammar({
         $.string,
       ),
       kw("language"), choice($.identifier, $.string),
-      optional($.function_volatility)
+      optional($.function_volatility),
+      optional($.function_run_as),
+    ),
+
+    function_run_as: $ => seq(
+      kw("security"),
+      choice(kw("invoker"), kw("definer"))
     ),
 
     function_return: $ => seq(