Innovation activities have become globalised and open in ways that were unimaginable 20 years ago. These changes have brought new insight into research on innovation activities and specific innovation practices in organisations, including that previous research largely ignored small and medium-sized enterprises (SMEs). This paper tests a variance-based structural equation model (SEM) for selected antecedents and determinants of commercialisation enablers on a sample of 105 SMEs from Slovenia – a small, open, post-transition economy with a dominant SME sector. The main contribution of the paper lies in testing how two specific open innovation practices (open innovation information exchange and open innovation collaboration) impact the commercialisation enablers of high-tech SMEs through their innovation activities (antecedent) and their innovativeness (determinant). Both open innovation practices show statistically significant effect on high-tech SMEs’ innovativeness, thus supporting the idea that both collaboration and information exchange lead to more innovativeness in high-tech SMEs. They also show a high impact of internal (organisational) factors on innovation activities of and a high impact of innovativeness on the commercialisation enablers of high-tech SMEs.