A needle assembly is disclosed, for use with an injection device. The needle assembly comprises a needle hub (20) having a needle (22) and a needle shield (40) arranged for relative axial movement with respect to the needle hub, between a retracted position in which the tip of the needle projects beyond a forward end of the shield and an extended position in which the tip of the needle does not project beyond the forward end of the shield. The needle shield (40) is axially biased towards the extended position. The needle shield (40) is further arranged to be torsionally biased for relative rotational movement with respect to the needle hub (20).
