A facemask penalty in Football is a penalty that is called on a team when a player grabs an opposing player by the facemask. In high school football and in most amateur leagues, any contact to the facemask constitutes a penalty. However, in the NFL and CFL, the twisting of the head due to the grab of a facemask is what defines the penalty. Contact can be made to the facemask in those leagues so long as no grabbing is performed. A facemask penalty results in a 15 yard loss, and an automatic 1st down if performed by the defense.
It should also be noted that the facemask penalty can be called when a grab is performed on any part of the helmet, including the ear holes or the chin strap.