In American football, an ineligible receiver is a player who cannot be the target of a forward pass during a football game. A player is determined ineligible based on his position at the time of the snap. When the ball is snapped, the offense is required to have no more than eleven players on the field, out of whom only six are eligible. On most plays, the eligible receivers include the quarterback, running backs, fullbacks, tight ends, and wide receivers, while the ineligible receivers are offensive linemen, including the center, offensive guards, and offensive tackles. However, the rule varies among leagues. In the National Football League (NFL), a quarterback is an ineligible receiver if he is directly under the center when he receives the snap. In college football, the NCAA allows ineligible receivers to be a maximum of 3 yards beyond the line of scrimmage before the pass is thrown.

If a forward pass is thrown while a player who is ineligible to receive a pass is beyond the line of scrimmage without blocking an opponent at the time of the pass, it results in a penalty called "ineligible receiver downfield". The penalty in both the NFL and NCAA is 5 yards. The referee will throw a penalty flag at the time the ineligible receiver goes downfield, and the offending team will then be assessed a five-yard penalty and will be forced to replay the down.