Genuine inclusive participation in the self-governance of communal irrigation systems remains a challenge. This article analyses the mechanisms of participation in irrigation water users’ associations (WUAs) with focus on women as leaders of those organizations by drawing on cases from a comparative, multicase mixed-method study in Ethiopia and Argentina. After having being a topic for decades in gender and development debates, in many irrigated areas of the world, WUAs continue to be male dominated at all levels, especially in influential positions. Findings in this article suggest that despite large socio-economic and cultural differences, the current water management systems in both research locations reinforce problems of unequal gender participation; women have more obstacles and constraints in establishing equal access in membership, participation, and decision making in irrigation management. The lack of inclusive participation and the low representation of women in leadership roles lead to WUAs being poorly rooted in their community of users. Incomplete social rootedness of WUAs jeopardizes their effectiveness and equality in water management and, as a result, affects long-term sustainability. Through analysis of empirical data of communal small-scale irrigation systems in both countries, the article discusses who participates, how and why they participate, and the reasons for low numbers of women in leadership roles within the WUAs. Finally, the article reflects on possible enabling conditions that could foster inclusive participation, increase the quantity and capacity of women in management and leadership roles, and the benefits this may bring to sustainable irrigation systems.