Access to safe water, sanitation and hygiene (WASH) services is crucial for every woman, man, girl and boy. Gender relations and roles directly influence access to WASH knowledge and practices. In light of women's often traditional role as stewards of water, their reproductive and menstrual health needs, their caring responsibilities, and their vulnerability to gender-based violence, access to water and sanitation is of utmost importance. This Tool provides guidance on how to tackle gender inequality in WASH and use WASH interventions to spark broader transformational change towards gender equality.