An injection device has contact surface 2119a for pressing against the skin of a patient and which is located at a first end of a sliding sleeve 2119 protruding, in its locked position preventing accidental actuation, from an injection device housing 112 and movable into the housing to an unlocked position. The contact surface 2119a may comprise an inwardly extending or radially extending flange or be at the end of a tapered or flared portion 2119b of the sliding sleeve 2119 to provide an improved contact area with reduced pressure against tissue and to minimize the risk of skin being trapped between the contact surface 2119a and the housing 112. The contact portion 2119a may be removable from the sliding sleeve 2119 and interchangeable with other contact portions, or retrofitted to existing devices. A cap may be provided.