Muhammad Youssef Al-Najjar (1930 - 10 April 1973), commonly known as Abu Youssef, was a Palestinian militant. Originally from Yibna, he began his involvement in the General Union of Palestinian Students. When the Fatah organization formed in the late 1950s, Youssef was an early activist, traveling to Qatar to form similar groups, and taking command of Fatah's military wing.