Abstract: A protective helmet including a chin cup with a body and two opposed connecting arms, each connecting arm being connected to the helmet body through a connection allowing relative movement between the connecting arm and the helmet body. A fastening system is selectively movable between a first position where the fastening system restrains the relative movement between the connecting arm and the helmet body and a second position where the fastening system frees the relative movement between the connecting arm and the helmet body along the connection. A method of adjusting a position of a chin cup in a protective helmet is also disclosed.