This paper investigates domestic and foreign innovating firms' determinants of R&D collaboration with domestic universities and public knowledge institutes in Finland and the Netherlands. We put particular emphasis on the impact of incoming academic spillovers on the probability to co-operate with these public R&D institutes. Based on data from Community Innovation Surveys we find that foreign firms in the Netherlands are less likely to co-operate with domestic public knowledge institutions than domestic firms, while in Finland no significant difference can be detected. Another result is that incoming knowledge spillovers are an important determinant for R&D collaboration with domestic public knowledge institutions in both countries. In case of foreign firms in Finland, incoming knowledge spillovers affect the probability to co-operate with public knowledge institutions more positively compared to domestic firms. For the Netherlands no substantial difference could be found in this respect. Further, innovating firms in Finland that require academic or basic knowledge do not co-operate significantly more with public knowledge institutions than those that need applied knowledge. At the same time they are willing to share knowledge with public R&D partners. In the Netherlands innovating firms that require relatively more basic than applied knowledge, increase the probability of co-operation with Dutch universities and public knowledge institutions but there is reluctance to share proprietary knowledge with public R&D partners. For both countries no significant difference between foreign and domestic firms with regard to academic knowledge requirements could be found. This raises the issue whether Finnish innovation policies with a strong focus on R&D co-operation provide incentives for strategic behaviour by domestic public partners to put more emphasis on applied research.