A drug delivery device for injecting medicament, the device comprising: a main body having a surface for contacting a patient; an actuation button distinct from the main body and movably disposed relative to the main body; a reservoir disposed within the main body for containing a medicament; at least one needle having: a distal end for insertion into the patient; and a lumen extending proximally from the distal end, wherein said lumen is fluidly connectable with the reservoir; wherein the drug delivery device further comprises a removable needle cover for selectively covering the distal end of the needle, the needle cover including: a needle cover portion; and a safety extension extending internally through the main body from the needle cover portion and adapted to engage the actuation button and prevent movement of the actuation button relative to the main body that initiates activation of the device; characterised in that the actuation button comprises a pair of cantilevered arms; and prior to needle cover removal, the safety extension extends between the cantilevered arms, preventing the cantilevered arms from moving toward each other and disengaging from engaging structures in the main body, thereby preventing movement of the actuation button relative to the main body that initiates activation of the device. a main body having a surface for contacting a patient; an actuation button distinct from the main body and movably disposed relative to the main body; a reservoir disposed within the main body for containing a medicament; at least one needle having: a distal end for insertion into the patient; and a lumen extending proximally from the distal end, wherein said lumen is fluidly connectable with the reservoir; a distal end for insertion into the patient; and a lumen extending proximally from the distal end, wherein said lumen is fluidly connectable with the reservoir; wherein the drug delivery device further comprises a removable needle cover for selectively covering the distal end of the needle, the needle cover including: a needle cover portion; and a safety extension extending internally through the main body from the needle cover portion and adapted to engage the actuation button and prevent movement of the actuation button relative to the main body that initiates activation of the device; a needle cover portion; and a safety extension extending internally through the main body from the needle cover portion and adapted to engage the actuation button and prevent movement of the actuation button relative to the main body that initiates activation of the device; characterised in that the actuation button comprises a pair of cantilevered arms; and prior to needle cover removal, the safety extension extends between the cantilevered arms, preventing the cantilevered arms from moving toward each other and disengaging from engaging structures in the main body, thereby preventing movement of the actuation button relative to the main body that initiates activation of the device. the actuation button comprises a pair of cantilevered arms; and prior to needle cover removal, the safety extension extends between the cantilevered arms, preventing the cantilevered arms from moving toward each other and disengaging from engaging structures in the main body, thereby preventing movement of the actuation button relative to the main body that initiates activation of the device.