Answer
Al-Qaeda was the terrorist organization Omar Khadr's father, Ahmed Said Khadr, was affiliated with. A prominent Al-Qaeda financier, Ahmed Khadr played a crucial role in facilitating the organization's activities and providing logistical support. His involvement with Al-Qaeda led to Omar Khadr's upbringing in a radicalized environment, shaping his worldview and influencing his subsequent involvement in extremist activities.