What factors might be causing the low participation of women Science, Technology, Engineering and Mathematics (STEM) fields? What can be done to attract more girls and women into STEM in Asia and beyond? The report, "A Complex Formula. Girls and Women in Science, Technology, Engineering and Mathematics in Asia", answers three fundamental questions: Where do we stand? What led us here? Where to from here? It examines a wide range of issues from gender differences in learning achievement in mathematics and science, participation in higher education as well as educational, psychosocial and labour market factors, all of which can influence girls' and women's attitudes towards STEM fields as a choice for further study and as a career. In today's fast-paced world, we face a multitude of challenges--climate change, global health epidemics, demographic changes, pressures from rapid technological advances and unprecedented inequality. These are but some of our most pressing concerns. While increased capacity and technical know-how are required to find new solutions to these challenges, women continue to remain a minority of STEM professionals worldwide. This report focuses on the findings based on a regional desk study, with research conducted in seven countries under review: Cambodia, Indonesia, Malaysia, Mongolia, Nepal, the Republic of Korea and Viet Nam. Along with these findings, the report also provides reflections and conclusions for further study and policy formulation in Asia and beyond. It is the second in a series of research studies as part of a three-year research project conducted by the UNESCO Asia and Pacific Regional Bureau for Education (UNESCO Bangkok) in collaboration with the Korean Women's Development Institute (KWDI), which aims to explore issues of gender, learning achievement and transition to the labour market. The following annexes are included: (1) Student Questionnaire; (2) Classroom Observation Sheet; (3) Guiding Questions for Semi-Structured Interviews in Indonesia; (4) Statistical Tables on Female Participation in STEM-Related International Olympiads by Country/Jurisdiction in 2014; and (5) Country-specific Policy Suggestions. [A bibliography is included. The following contributed input for this report: Gwang-Chol Chang, Ramya Vivekanandan Rodrigues, Tserennadmid Nyamkhuu, and Antony Tam.]