The impact of women participation in agricultural value chains into their empowerment is poorly understood. This paper explores the linkage between women’s participation in onion value chain development activities and their empowerment. The study involved 402 women of whom 207 (51.2%) were participating in the onion value chain development activities and 195(48.5%) were non non-participants. Data was analyzed using SPSS program, four index scales were constructed to measure women empowerment (personal autonomy, household decision making, economic domestic consultation and freedom of movement). A composite women empowerment index was developed to gauge women empowerment. Women in Simanjiro District were categorized in medium level of empowerment (mean score on CEI = 0.6033). Empowerment was found to increase with education attainment, age at first marriage and women income. Generally, women participating in the value chain development programme were more likely to be empowered than their counterparts. Ordinal logistic regression analysis revealed that there was a significant relationship between women empowerment and marital status, education level, age at first marriage, land ownership, access to credits and participation in onion value chain (P<0.05). The study recommends to the government, non-governmental organization and farmers groups to introduce gender and life skills education in value chain programmes to sensitize and mobilize actors to challenge gender inequalities and promote women empowerment.