Collective actions groups have many advantages and are sometimes essential, yet they can reinforce or perpetuate inter-and intra-gender inequalities when their functioning is left entirely subject to internal community dynamics and they are not well managed. This is well illustrated by the case of Koussin-Lélé rice scheme in the central Benin. This paper apply inequality indices and frontier production function to data from a sample of male and women rice farmers to analyze the gender inequalities in access to land and the governance of the groups, and their gender-differentiated impacts on farmers' productivity, technical efficiency and income. The results show that women are particularly discriminated against with regards to access to land, with significant negative impacts on their productivities and incomes. However, this discrimination did not have a significant impact on technical efficiency.