The notion of open innovation suggests that firms can boost their innovative performance by both acquiring knowledge from outside the company and deploying external paths to market for commercialization of non-core technologies. As innovations emerge increasingly from interorganisational cooperation, the background for such cooperation can also have an impact on the involvement of companies into open innovation processes. Thereby this paper proposes to analyze the barriers towards open innovation from three different aspects, such as internal firms' environment, institutional factors or innovation system and cultural background. Our findings indicate that economic systems and institutions (in particular the protection of IPRs) may have large effects on the behaviour of firms with respect to their engagement in open innovation practices. On the other hand, our results also suggest that the importance of appropriability regime may differ in the buy and sell sides of knowledge, and finally we demonstrate the influence of peculiarities of national cultures upon the adoption of certain elements of open innovation model.