The invention provides an injection device for delivering a dose of medicament from a syringe. The injection device comprises a housing (10), a plunger (110) moveably mounted within the housing, an actuation mechanism (120, 122) arranged to provide a forward biasing force to urge the plunger forward in use to express a dose of medicament and a trigger mechanism (40) arranged to (directly or indirectly) releaseably hold the plunger against the force of the actuation mechanism. The injection device further comprises a plunger velocity regulator comprising a cam surface (162) associated with one of the housing or the plunger, and a cam member (152) associated with the other of the plunger or the housing and arranged to engage the cam surface during actuation movement of the plunger such that axial movement of the plunger relative to the housing causes relative rotational movement of the cam member and limits the forward velocity of the plunger movement.
