This Guidance Note highlights key points for gender integration in the research for development (R4D) project cycle. It uses an intersectional lens to recognize how aspects of social identity such as age or life stage, class, caste, ethnicity, ability, sexual orientation and so forth crosscut and shape gender and power. This Guidance Note has been designed for use by R4D teams and researchers working in food systems. The content was originally created for teams working in aquatic food systems, particularly small-scale fisheries and aquaculture. But this version is framed broadly so that it can be useful to those working in any area of food systems. After an introduction (section 1), the Note explain why adopting a gender lens is important (Section 2) . Section 3 explains the “What,” “When” and “Which approaches” to take. Section 4 dives into the building blocks of what is involved in applying an intersectional gender lens. Section 5 moves into the “How” in relation to each phase of the project cycle. Finally, Section 6 wraps up six key principles as reminders to take away.