An dual-dose syringe system is an apparatus that includes a tubular housing and a plunger. The tubular housing attaches onto a variety of syringe and needle assemblies and mounts the plunger within the syringe. The tubular housing prevents the plunger from simply traversing into the syringe. The tubular housing includes a first lateral-half portion and a second lateral half-portion that snaps onto each other and encloses a syringe. The tubular housing further includes a key slot that engages the plunger. The plunger includes a plurality of cross bars that predetermine two doses. Each of the plurality of cross bars is positioned perpendicular to a corresponding adjacent bar, forcing a user to purposefully twist the plunger in order to administer a dose. The apparatus further includes at least one spring-loaded barb that prevents the reuse of the apparatus.