A handling device for use with a medical injector (11) including a protective sheath (17) for a needle (14) has a carrier (20) with an outer cylindrical wall (21) and a coaxial inner tube (33) which is a close sliding fit over the protective sheath (17). A cylindrical sleeve (24) is slidably mounted within the outer cylindrical wall (21) and is adapted to receive the cylindrical body (12) of the injector (11). A bushing (25) is slidably retained within the cylindrical sleeve (24) and is configured to receive a boss (13, 15) supporting the needle (14) at the forward end of the injector body, a spring (29) urging the bushing (25) towards the rear of the sleeve. A plug (35) is mounted on the carrier (20) and is engaged by the forward end of the protective sheath (17) when the injector is received within the cylindrical sleeve, so that the plug is projected forwardly from the carrier when the injector is fully engaged. On removing the carrier (20) from the injector (11), the plug (35) remains projecting therefrom and the sheath (17) is removed together with the carrier.