Described is a needle assembly (5) comprising a needle (10) and a hub (15, 30, 40, 55) coupled to the needle. The hub (15, 30, 40) includes an engagement member (20, 45, 60) adapted to engage an attachment arrangement on a medicament delivery device and a stop member (25, 50, 65) adapted to abut the attachment arrangement to prevent proximal movement of the needle assembly (5).