Following a network approach, this study aims to understand the potential of inter-organizational relationships in clusters for sharing knowledge and innovation. To this end, qualitative research of an exploratory nature was undertaken, with the information being gathered through interviews with owners and managers of small and medium-sized family enterprises belonging to an agro-industrial cluster in Portugal. Through content analysis, the results obtained showed that clustering 1 promotes the publicizing and internationalization of products and has an impact on small and medium-sized enterprises’ (SME) results. The importance of the cluster’s action regarding innovation was also confirmed, and so was its potential as a catalyst for the sharing of knowledge. Business-people’s attitude and relational competences, particularly trust, mutual help and having an open mind, were found to be essential factors for successful network functioning and the clustering process. Therefore, this study contributes to the developing existing theory by analysing clustering as inter-organizational networks of sharing knowledge and innovation activities in the light of the network theory and its association with resource-based and knowledge-sharing theories.