diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 0b3b8e98b80..c7ecedbe3bc 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1011,10 +1011,13 @@ DefineIndex(Oid tableId,
 			{
 				if (key->partattrs[i] == indexInfo->ii_IndexAttrNumbers[j])
 				{
-					/* Matched the column, now what about the equality op? */
+					/* Matched the column, now what about the collation and equality op? */
 					Oid			idx_opfamily;
 					Oid			idx_opcintype;
 
+					if (key->partcollation[i] != collationIds[j])
+						continue;
+
 					if (get_opclass_opfamily_and_input_type(opclassIds[j],
 															&idx_opfamily,
 															&idx_opcintype))