Collaboration is a term commonly used to refer to a type of inter-organizational relationship. However, in real business assessments, many collaborative relationships fail due to the lack of understanding of the factors influencing collaboration sustainability. For this reason, enterprises, prior to engage to a collaborative relationship, need to understand further which the main factors influencing collaboration relationships are, how they are structured and how they interact so that decision makers that desire to engage in a collaborative relationship/network focus not only on improving performance indicators but also on the factors that influence the results of those performance indicators. The purpose of this paper is to present a critical literature review of factors influencing collaborative relationships in order to perform a comparative study of the works for identifying main strengths and gaps for future research.