Frank Thrall Weatherwax (June 23, 1902 – December 17, 1991) was an American actor and animal trainer. He is best remembered with his brother Rudd Weatherwax for their famous collie, Pal, the dog who became famous as Lassie in the 1943 Metro-Goldwyn-Mayer film Lassie Come Home. He also trained the dog, Lightning, for the 1935 movie A Dog of Flanders.