A needle safety system for a syringe, the needle safety system comprising: a sleeve configured to partially enclose a needle of a syringe; a guide track formed in the sleeve; and a collar disposed in the sleeve, the collar comprising: an inner collar portion configured to fixedly attach to a hub of a syringe, the inner collar portion having a generally cylindrically-shaped base with an inner-collar bore therethrough; an outer collar portion rotatably attached to the inner collar portion, the outer collar portion having an outer collar bore with a radially inwardly-extending outer collar ring; and at least one guide pin extending radially from the outer collar portion, the guide pin configured to side within the guide track; and a spring extending between the outer collar portion and the sleeve, the spring biasing the sleeve in a distal direction and also biasing the outer collar portion in rotation relative to the sleeve; wherein the inner collar portion defines a circular channel configured to receive and retain freely rotatable therein the radially inwardly-extending outer collar ring, characterized in the outer collar portion being of unitary construction and having at least one accordion region which is radially compressible and expandable. a sleeve configured to partially enclose a needle of a syringe; a guide track formed in the sleeve; and a collar disposed in the sleeve, the collar comprising: an inner collar portion configured to fixedly attach to a hub of a syringe, the inner collar portion having a generally cylindrically-shaped base with an inner-collar bore therethrough; an outer collar portion rotatably attached to the inner collar portion, the outer collar portion having an outer collar bore with a radially inwardly-extending outer collar ring; and at least one guide pin extending radially from the outer collar portion, the guide pin configured to side within the guide track; and a spring extending between the outer collar portion and the sleeve, the spring biasing the sleeve in a distal direction and also biasing the outer collar portion in rotation relative to the sleeve; wherein the inner collar portion defines a circular channel configured to receive and retain freely rotatable therein the radially inwardly-extending outer collar ring, characterized in the outer collar portion being of unitary construction and having at least one accordion region which is radially compressible and expandable. an inner collar portion configured to fixedly attach to a hub of a syringe, the inner collar portion having a generally cylindrically-shaped base with an inner-collar bore therethrough; an outer collar portion rotatably attached to the inner collar portion, the outer collar portion having an outer collar bore with a radially inwardly-extending outer collar ring; and at least one guide pin extending radially from the outer collar portion, the guide pin configured to side within the guide track; and a spring extending between the outer collar portion and the sleeve, the spring biasing the sleeve in a distal direction and also biasing the outer collar portion in rotation relative to the sleeve; wherein the inner collar portion defines a circular channel configured to receive and retain freely rotatable therein the radially inwardly-extending outer collar ring, characterized in the outer collar portion being of unitary construction and having at least one accordion region which is radially compressible and expandable.