Julius Onah (born February 10, 1983) is an American-Nigerian film director, screenwriter, and producer. He is best known for directing the feature films, The Cloverfield Paradox (2018), Luce (2019), and Captain America: Brave New World (2025).

Onah was born in Cross River State, Nigeria, in Okpoma. Adoga Onah, his father, was a diplomat from Nigeria. Before relocating to Arlington County, Virginia, he was raised in the Philippines, Nigeria, Togo, and the United Kingdom. After graduating from Arlington, Virginia's Washington-Lee High School, Onah went on to get a bachelor's degree in drama from Middletown, Connecticut's Wesleyan University. He earned an M.F.A. from New York University's Tisch School of the Arts' graduate film course, where he also qualified as a Dean's Fellow. Additionally, he has been awarded the esteemed Jack Kent Cooke Foundation Scholarship.