Onion (Allium cepa L.) is one of the major cash crops grown mostly in northern Nigeria, nevertheless with perpetual scarcity at off season due to its perishability as actors lacked adequate storability thus, sells at low price to avoid spoilage at hand. The study seeks to evaluate onion value chain actors (producers and retailers) in Kebbi State, Nigeria. Purposive, simple random and convenience sampling procedures were used in selecting 210 onion producers and 40 retailers using structured questionnaire. The data collected was analyzed using SPSS software and marketing margin model. The result of the study revealed that the mean output of onion per hectare was 71.58 bags with an average price of ₦15597.05. The total gross marketing margin of 14.38% out of 19.12% constitutes the total marketing costs with net marketing margin of 4.77%. Producers’ and retailers’ marketing profit share was ₦9331.61 and ₦2324.33 per bag respectively. Production and marketing constraints identified were; high cost of inputs, pest and disease attack, poor storage facilities and poor pricing. In conclusion, redress of constraints may enhance marketing margin of the actors. The study recommends for government/nongovernmental sustainable financial, technical and educational interventions for the value chain improvement in the study area.