Women’s collective action (WCA) has provided significant opportunities for women to increase their role in vegetable markets in Tanzania, and enhances the benefits which they derive from this sector. Women already perform much of the labour needed to grow vegetables, whether in their own households or as casual labourers. However, men own most of the fertile valley land on which vegetables are grown, and dominate the trade to Dar es Salaam and other urban centres within Tanzania and neighbouring countries. Men enjoy correspondingly greater control over incomes from vegetable marketing. Women, on the other hand, generally struggle to raise the funds to invest in land and irrigated vegetable production, and are often prevented from trading over long distances by their domestic responsibilities, and by attitudes which discourage women from sleeping away from home. Research carried out in Lushoto district, Tanzania, shows that involvement in collective action (CA) leads to significant economic benefits to women from vegetable production and marketing. Not only have women members’ incomes increased, but in some cases this has enabled them to invest more in the development of their households and the welfare and education of their children.