diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 739ea13d5db..ea97d236ea8 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -4002,6 +4002,15 @@ transformLockingClause(ParseState *pstate, Query *qry, LockingClause *lc,
 											LCS_asString(lc->strength)),
 									 parser_errposition(pstate, thisrel->location)));
 							break;
+						case RTE_GRAPH_TABLE:
+							ereport(ERROR,
+									(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							/*------
+							  translator: %s is a SQL row locking clause such as FOR UPDATE */
+									 errmsg("%s cannot be applied to GRAPH_TABLE",
+											LCS_asString(lc->strength)),
+									 parser_errposition(pstate, thisrel->location)));
+							break;
 
 							/* Shouldn't be possible to see RTE_RESULT here */
 
diff --git a/src/test/regress/expected/graph_table.out b/src/test/regress/expected/graph_table.out
index a3d78a7ac43..46566b2e32f 100644
--- a/src/test/regress/expected/graph_table.out
+++ b/src/test/regress/expected/graph_table.out
@@ -1106,4 +1106,17 @@ SELECT src.vname, count(*) FROM v1 AS src
  v13   |     1
 (3 rows)
 
+-- Locking clause on GRAPH_TABLE
+SELECT * FROM GRAPH_TABLE (g1 MATCH (src IS vl1) COLUMNS (src.vname)) gt FOR UPDATE OF gt;  -- not supported
+ERROR:  FOR UPDATE cannot be applied to GRAPH_TABLE
+LINE 1: ...MATCH (src IS vl1) COLUMNS (src.vname)) gt FOR UPDATE OF gt;
+                                                                    ^
+SELECT * FROM GRAPH_TABLE (g1 MATCH (src IS vl1) COLUMNS (src.vname)) gt FOR UPDATE;  -- ignored
+ vname 
+-------
+ v11
+ v12
+ v13
+(3 rows)
+
 -- leave the objects behind for pg_upgrade/pg_dump tests
diff --git a/src/test/regress/sql/graph_table.sql b/src/test/regress/sql/graph_table.sql
index 6aacc2d4aa5..3fb0e50ddb2 100644
--- a/src/test/regress/sql/graph_table.sql
+++ b/src/test/regress/sql/graph_table.sql
@@ -619,4 +619,8 @@ SELECT src.vname, count(*) FROM v1 AS src
   HAVING count(*) >= (SELECT count(*) FROM GRAPH_TABLE (g1 MATCH (a IS vl1 | vl2) COLUMNS (a.vname AS n)) WHERE n = src.vname)
   ORDER BY vname;
 
+-- Locking clause on GRAPH_TABLE
+SELECT * FROM GRAPH_TABLE (g1 MATCH (src IS vl1) COLUMNS (src.vname)) gt FOR UPDATE OF gt;  -- not supported
+SELECT * FROM GRAPH_TABLE (g1 MATCH (src IS vl1) COLUMNS (src.vname)) gt FOR UPDATE;  -- ignored
+
 -- leave the objects behind for pg_upgrade/pg_dump tests