diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 3ba43a3edaf..3097ec53c10 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -2344,6 +2344,17 @@ MergeWithExistingConstraint(Relation rel, char *ccname, Node *expr,
 						 errmsg("constraint \"%s\" conflicts with non-inherited constraint on relation \"%s\"",
 								ccname, RelationGetRelationName(rel))));
 
+			/*
+			 * Must not change an existing inherited constraint to "no
+			 * inherit" status.  That's because inherited constraints should
+			 * be able to propagate to lower-level children.
+			 */
+			if (con->coninhcount > 0 && is_no_inherit)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+						 errmsg("constraint \"%s\" conflicts with inherited constraint on relation \"%s\"",
+								ccname, RelationGetRelationName(rel))));
+
 			/*
 			 * If the child constraint is "not valid" then cannot merge with a
 			 * valid parent constraint
diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out
index fa3d9029417..978d3a1a339 100644
--- a/src/test/regress/expected/inherit.out
+++ b/src/test/regress/expected/inherit.out
@@ -646,6 +646,9 @@ Check constraints:
     "p2chk" CHECK (ff1 > 10)
 Inherits: p1
 
+-- Test that child does not override inheritable constraints of the parent
+create table c2 (constraint p2chk check (ff1 > 10) no inherit) inherits (p1);	--fails
+ERROR:  constraint "p2chk" conflicts with inherited constraint on relation "c2"
 drop table p1 cascade;
 NOTICE:  drop cascades to table c1
 -- Tests for casting between the rowtypes of parent and child
diff --git a/src/test/regress/sql/inherit.sql b/src/test/regress/sql/inherit.sql
index b64221f7eea..8bc5ef4813d 100644
--- a/src/test/regress/sql/inherit.sql
+++ b/src/test/regress/sql/inherit.sql
@@ -157,6 +157,9 @@ create table c1 () inherits (p1);
 \d p1
 \d c1
 
+-- Test that child does not override inheritable constraints of the parent
+create table c2 (constraint p2chk check (ff1 > 10) no inherit) inherits (p1);	--fails
+
 drop table p1 cascade;
 
 -- Tests for casting between the rowtypes of parent and child