We use a self-consistent mean-field theory which accounts for polymer semiflexibility to study the effects of semiflexible copolymers localized at the interface between a flexible and a semiflexible homopolymer. Our studies show that, in contrast to copolymers located at the interface between flexible polymers, entropic effects tend to dominate the behavior of the copolymers at semiflexible polymer interfaces. We find that the reduction in interfacial tension caused by the copolymer is a nonmonotonic function of the rigidity of the copolymer and the amount of copolymer added to the system.