Riley A. Thomson Jr. (October 5, 1912 – January 26, 1960) was an American animator and comics artist who spent most of his career working with Walt Disney films and characters.
He directed six Disney short films including The Nifty Nineties and Symphony Hour.
He was first an animator and worked on Mickey Mouse, Silly Symphonies, and Donald Duck short films.
He also worked on the feature-length film Snow White and the Seven Dwarfs (1937) and "The Sorcerer's Apprentice" segment of Fantasia (1940).
He directed the short films Put-Put Troubles (1940), The Little Whirlwind (1941), The Nifty Nineties (1941), the 1941 remake of Orphans' Benefit, Mickey's Birthday Party (1942), and Symphony Hour (1942).