In a complex project, an organization is often not able to manage all aspects alone, since it does not have all the required competences, skills or resources. In this case, alliance formation can be a solution for project development. Apart from simply managing complex projects, firms also find it important to increase innovativeness by sharing knowledge between partners in alliances. However, in alliances one of the difficulties is achieving effective collaboration: mis-communication, missing skills or missing resources create a high risk that the project fails to achieve its goals. In order to decrease the risk of failure, and to overcome potential collaboration inefficiency, partner selection takes place among firms that are able to communicate well while at the same time having the required knowledge to achieve their objectives. The important role of partner selection in alliances justifies the increased attention given to substantial criteria in alliance formation. Proposing a knowledge-based framework aimed at increasing the understanding of partner selection in alliances is the contribution of this paper. This knowledge can be gained by evaluating projects from a technological point of view to estimate their challenging degrees, and studying the partners background in past projects or partnerships. This paper structured to propose hypotheses based on a systematic literature review. At the heart of the hypotheses is a consideration of the needs of the project, and starting there allows us to characterize alliance formation and partner selection using a new typology. Finally, a novel framework is proposed that could help decisionmakers in the managerial aspects of partner selection in alliance formation. The framework also presents considerable potential for future studies.