Purpose: Co-creation along the new product development (NPD) seems the winning approach in nowadays market. The purpose of this paper is to explore the collaboration and interaction flows between suppliers and customers in co-creation initiatives devoted to NPD. Design/methodology/approach: After developing a classification of demand-side and supply-side involvement in co-creation along the NPD process, 13 cases of co-creation in the consumer goods industry, within the Italian context, have been analyzed. Findings: Three patterns of co-creation have been identified: supplier-driven approach: companies co-creating with suppliers in multiple NPD phases, while involving customers only in one; customer-driven approach: companies involving customers in multiple phases, while engaging suppliers only in one and firm-driven approach: companies involving both customers and suppliers in one single phase. Further, the locus of relevant knowledge drives to different co-creation approaches. Research limitations/implications: The work contributes to extant literature by: providing a classification of demand-side and supply-side involvement in NPD; empirically investigating the interaction flows between customers and suppliers in co-creation initiatives along the NPD; highlighting the factors potentially affecting a concurrent involvement of customers and suppliers in NPD. Practical implications: The findings can help to efficiently and effectively design and manage the relation with both suppliers and customers in co-creation projects devoted to NPD. Originality/value: The involvement of suppliers and customers in co-creation initiatives has been so far analyzed only separately in literature. This study opens a new stream of research, stressing how the evolution of the market, toward a more participative one, spurs the need to investigate the collaboration and interaction flows between the two actors