This Guidebook on Mainstreaming Gender in the Implementation of the Montreal Protocol (hereinafter referred to as the guidebook) has been developed to help advance the agenda of gender equality and women’s empowerment under the implementation of Montreal Protocol by means of the NOUs and national stakeholders mainstreaming gender issues into their daily works and operations. The Guidebook maps the existing issues and challenges in achieving gender equality through Montreal Protocol activities, identifies gender mainstreaming opportunities under the implementation of Montreal Protocol along with examples and good practices from various countries. The guidebook has been developed through an iterative process that included a review of MLF-related documents (global and country level), including selected MLF projects proposals, work programmes and progress reports, evaluation reports and related documents, consultation with selected NOUs and the four implementing agencies, a questionnaire survey covering 29 NOUs, which yielded further information about gender related achievements and challenges.