The group began spewing hate on Twitter just one day after the "Fast & Furious" star and his friend died from a fiery car crash in Santa Clarita, Calif. on Saturday.
Members of the controversial religious sect are known for protesting same-sex marriage and military funerals, among tragedies around the world.
In May, the church planned to picket the funeral of a 9-year-old boy who died during the tornadoes in Moore, Okla., but they were met by a large motorcycle group who blocked the protest.
Walker's family has not yet announced funeral arrangements or a date. There's no word if any groups plan to block Westboro's protest.