Of course! Many grandparents, parents, aunts and uncles open up an RESP as a gift to a child, perhaps for a birthday or other important milestone. And what a gift! Education is something that will help that child throughout life. It keeps giving, and giving, and giving.
Keep in mind, there’s a limit on the total RESP contributions and grants that each child is allowed to receive. So if a child has multiple RESPs in their name, you’ll need to coordinate with the other RESP subscribers. Another alternative is to give a cash gift to the parents who already have an RESP for them to contribute to the child’s RESP.