Nikki van der Gaag is an independent gender consultant, and a Senior Fellow at Equimundo (formerly Instituto Promundo), and until January 2019 was Director of Gender Justice and Women’s Rights at Oxfam GB. She is on the Board of Make Mothers Matter and a member of the Steering Committee of MenEngage Europe. She has written extensively on gender, feminism and the inclusion of men and boys in gender equality, and has a particular interest in unpaid care. Books and reports include Feminism and Men (Zed Books 2014), the No-nonsense guide to Feminism (New Internationalist 2017), authoring six State of the World’s Girls reports, including one on boys, and co-authoring four State of the World's Fathers reports.

She has been working with Young Lives as a consultant for more than 10 years, including a period on the International Advisory Board.