This presentation aims to show the high degree of heterogeneity in the effect of Science and Technology Parks (STPs) on the innovation performance of tenants. We use patent quality as an innovation indicator due to the importance of taking into account the value of innovations. Our findings show STPs impact more on younger and larger firms when considering firm characteristics as potential heterogeneity sources. Regarding the characteristics of Parks themselves, we can see that older and young STPs have a positive impact on patent quality and the impact of university parks and non-university parks is similar, so there is no significant difference between them.