Described is a stackable, heat-insulating paperboard cup having an inner sleeve and an outer sleeve with a gap therebetween. A rolled lip is applied to the lower end of the outer sleeve, which rolled lip is disposed on the inner sleeve. A shoulder is formed on the inner sleeve for the rolled lip of another paperboard cup to be stacked. The diameter of the inner sleeve below the shoulder is reduced discontinuously. The support of the lower rolled lip on the outer surface of the inner sleeve is arranged at the same level as, or below, the cup bottom.