Attachment systems for releasably securing an accessory to an article, such as a helmet, are disclosed. In one embodiment, an attachment system includes an attachment plate that includes engaging features which engage corresponding engagement features on an attachment base. At least one of the engaging features on the attachment plate is associated with a flexible member, and is movable between a locked configuration and an unlocked configuration via deformation of the flexible member. A pair of grips are provided on opposing ends of the flexible member, and the grips are pressed toward one another to move the movable engaging feature between the locked and unlocked configurations.