This is a disambiguation page for "Grandpa Duck". By "Grandpa Duck", you might mean:
- Grandpa Duck, birth name Humperdink Duck, the paternal grandfather of Donald Duck and late husband of Grandma Duck;
- Grandpa Duck, Donald's "Grandpa Duck" from No Hunting (1955), who may or may not be the same character as Humperdink;
- Grandpa Ostman, the "Grandpa" mentioned by Donald Duck in The Hard Loser (1943), retconned to be the grandfather of Huey, Dewey and Louie Duck on the non-Duck side of their family.