Purpose: This article explores the Triple Helix model and conceptualizes the role of Technology Transfer Offices (TTOs) as intermediaries for the valuation and commercialization of the knowledge generated at universities and research centers. The result is a synthesis of the main research lines that have been examined during the last years. This paper also identifies new research avenues that have remained underexplored in the literature but represent an interesting starting point for future studies. Undoubtedly, these new lines would provide a better understanding of the real internal functioning of TTOs and its importance as an interface between the academic and the business world. Design/methodology/approach: Through a bibliometric study those papers published in journals indexed in the ISI Web of knowledge and Scopus have been identified, and because of their relevance and their international scope have been selected and included in this literature review. Findings: This paper allows us to in-depth in the Triple Helix model III and its performance when considering TTOs as knowledge brokers. Originality/value: Two are the main contributions that this article does to the existing scientific literature on technology transfer: 1) the identification and organization of the literature and approaches covered in previous studies, and 2) the identification of different research lines that have not yet been widely explored in the current literature, but that can help explain the performance of TTOs.Postprint (published version