diff --git a/src/cst/Merge.ts b/src/cst/Merge.ts
index cd902fc9..caebc10f 100644
--- a/src/cst/Merge.ts
+++ b/src/cst/Merge.ts
@@ -1,7 +1,7 @@
 import { Alias } from "./Alias";
 import { BaseNode, Keyword } from "./Base";
 import { Expr, Identifier, ListExpr, ParenExpr, EntityName } from "./Expr";
-import { DefaultValues, ValuesClause } from "./Insert";
+import { DefaultValues, OverridingClause, ValuesClause } from "./Insert";
 import { SelectStmt, WithClause } from "./Select";
 import { SetClause } from "./Update";
 
@@ -82,7 +82,12 @@ export interface MergeActionInsert extends BaseNode {
   type: "merge_action_insert";
   insertKw: Keyword<"INSERT">;
   columns?: ParenExpr<ListExpr<Identifier>>;
-  clauses: (ValuesClause | DefaultValues | MergeActionInsertRowClause)[];
+  clauses: (
+    | OverridingClause
+    | ValuesClause
+    | DefaultValues
+    | MergeActionInsertRowClause
+  )[];
 }
 
 // BigQuery
diff --git a/src/parser.pegjs b/src/parser.pegjs
index e4e8af16..0cef7325 100644
--- a/src/parser.pegjs
+++ b/src/parser.pegjs
@@ -1733,12 +1733,16 @@ merge_action_update
 
 merge_action_insert
   = insertKw:(INSERT __) columns:(paren$list$column __)?
+    overriding:(overriding_clause __)?
     values:(values_clause / default_values / merge_action_insert_row_clause) {
       return loc({
         type: "merge_action_insert",
         insertKw: read(insertKw),
         columns: read(columns),
-        clauses: [values],
+        clauses: [
+          read(overriding),
+          values
+        ].filter(identity),
       });
     }
 
diff --git a/test/dml/merge.test.ts b/test/dml/merge.test.ts
index bd4eefc6..3bf01271 100644
--- a/test/dml/merge.test.ts
+++ b/test/dml/merge.test.ts
@@ -105,6 +105,19 @@ describe("merge into", () => {
         it("supports INSERT DEFAULT VALUES", () => {
           testWc("MERGE INTO foo USING bar ON x=y WHEN NOT MATCHED THEN INSERT DEFAULT VALUES");
         });
+
+        it("supports INSERT OVERRIDING SYSTEM/USER VALUE", () => {
+          testWc(`
+            MERGE INTO foo USING bar ON x=y
+            WHEN NOT MATCHED THEN
+            INSERT OVERRIDING SYSTEM VALUE VALUES (1, 2)
+          `);
+          testWc(`
+            MERGE INTO foo USING bar ON x=y
+            WHEN NOT MATCHED THEN
+            INSERT OVERRIDING USER VALUE VALUES (1, 2)
+          `);
+        });
       });
 
       dialect("bigquery", () => {