A needle assembly for mounting on an injection device which comprises a body configured to be attached to an injection device in use; a double ended needle; and a needle shield coupled to the body. The needle shield is arranged for axial movement with respect to the body. The needle assembly has an injection configuration, in which the shield is positioned such that the forward tip of the needle projects beyond a forward end of the shield. The needle assembly also has a shroud configuration, in which the shield is positioned such that the forward end of the shield extends beyond the forward tip of the needle. The needle assembly further comprises a needle support fixed relative to the body when the needle assembly is in the injection configuration. Movement of the shield from the injection configuration to the shroud configuration axially displaces the needle support relative to the body.