(The concept of the Bioeconomy addresses complex societal issues where multiple dimensions are in conflict, and a range of scientific and practical knowledge is required to find solutions. This chapter sets out definitions, principles and tools for conducting inter- and transdisciplinary research in the context of bioeconomy. Our objective is to provide readers with a comprehensive understanding of inter- and transdisciplinary research approaches and to equip them with the concepts, skills and instruments required for the design, planning, implementation and evaluation of such research. Our disciplinary background in social sciences in agriculture guides our approach towards the bioeconomy, including the presentation of case studies, utilisation of concepts, methodologies and tools. In the sections of this chapter, we focus on the justification of inter- and transdisciplinary research in the bioeconomy (► Sect. 37.1), on the characteristics of the inter- and transdisciplinary research process (► Sect. 37.2) and on methods and tools to make collaboration effective and efficient (► Sect. 37.3). Finally, we highlight particularly the roles, responsibilities and agencies that researchers have when engaging in inter- and transdisciplinary research (► Sect. 37.4).