A drug delivery device for injecting medicament, the device including a main body having a surface for contacting a patient, an actuation button (110, 420, 436) movably disposed relative to the main body, and a reservoir disposed within the main body for containing a medicament. The device also includes a needle having a distal end for insertion into a patient, and a lumen extending proximally from the distal end, wherein the lumen is fluidly connectable with the reservoir. The device further includes a removable needle cover (114, 400) for selectively covering the distal end of the needle and selectively preventing movement of the actuation button relative to the main body that initiates activation of the device.