Nikko is the leader of the Flying Monkeys and the secondary antagonist in the 1939 MGM film The Wizard of Oz. He is the movie version of the character called the Monkey King in L. Frank Baum's original novel The Wonderful Wizard of Oz. Unlike the literary character, the cinematic Nikko does not talk.
In the MGM film, Nikko was played by Pat Walshe, a veteran animal actor, performing with Margaret Hamilton as the Wicked Witch of the West.
In the 1990 DIC cartoon, he is renamed "Hamm".