William Roscoe Leake (April 12, 1961 – September 2, 2006), better known as Willi Ninja, was an American dancer and choreographer known for his appearance in the documentary film Paris Is Burning.

Ninja specialized in voguing and was a fixture of ball culture at Harlem's drag balls who took inspiration from sources as far-flung as Fred Astaire and the world of haute couture to develop a style of dance and movement. He caught the attention of Paris Is Burning director Jennie Livingston. The film served as a springboard for Ninja. He parlayed his appearance into performances with a number of dance troupes and choreography gigs.

In 1989, Ninja starred in the music video for Malcolm McLaren's song "Deep in Vogue", which sampled the then-unfinished movie.

Ninja was a member of the LGBT community who died of AIDS complications in 2006.