The invention relates to a sleeve for an injection device comprising a container having an outer flange, said sleeve being provided with one inner radial projection intended to prevent the proximal movement of said outer flange with respect to said sleeve once said container is received within said sleeve, said sleeve being further provided with one inner longitudinal projection extending distally from said inner radial projection and intended to limit the radial movement of said outer flange, said inner radial projection and inner longitudinal projection being provided on a longitudinal leg connected to said sleeve by a deformable bridge allowing radial deflection of said longitudinal leg outwardly when a distal pressure is exerted on said inner radial projection, and inwardly when a proximal pressure is exerted on said inner radial projection. The invention also pertains to an injection device comprising such a sleeve.