The study of modes of open innovation in smaller companies is still in the development phase. This study responds to this situation and, drawing upon a data set from 4,679 Turkish small and medium-sized enterprises (SMEs), explores the influence of inbound open innovation and coupled open innovation on marketing innovation as well as process and organisational innovation in SMEs. Results reveal major differences between small and medium-sized Turkish enterprises with regard to both marketing innovation as well as process and organisational innovation. While inbound open innovation positively influences both, marketing as well as process and organisational innovation, the effects for small-sized enterprises are even higher than for medium-sized ones. Coupled open innovation positively influences both innovation outcomes as well, although the effects for medium-sized enterprises are significantly higher than for smaller ones.