It is argued that gender roles and relations determine distribution of benefits accrued from ones’ participation in value chain activities. But many value chain programmes are commonly designed and implemented without taking into consideration gender roles and relations. This study analysed onion value chain to determine its impact on gender roles, relations and distribution of income in the chain. The study adopted a mixed-methods design where focus group discussions, key informant interviews and household survey which were the main methods for data collection. Evolution in gender roles especially in production activities was found. Women participation in onion value chain activities, leadership in farmers’ organisation and in decision making over the income accrued from onion production was found to increase following interventions to develop the onion value chain. However, their participation in marketing of onion is constrained by many factors, including limitation on movement placed by their husbands or male partners. This study recommends to government and non-governmental organisations using value chain intervention to address gender roles and relation in value chain development activities to facilitate equitable access by rural producers’ men and women to agricultural inputs as and facilitate access to market of their crops and products. Gender sensitive intervention strategies should be used in forming and strengthening farmer organizations to competitively participate in onion value chain and increase women participation and benefit from onion production.