The timely availability of improved seeds at affordable prices is critical to improving food security, resilience, and livelihoods for smallholder farmers in Nigeria. Seed of improved varieties can deliver state-of-the-art technology to farmers including higher yields, disease and pest resistance, climate change adaptation, and improved nutrition. This report summarizes the key findings of the study conducted by The African Seed Access Index (TASAI) to appraise the structure and economic performance of Nigeria’s formal seed sector. With a focus on the four grain and legume crops important to national food and nutritional security (maize, rice, sorghum, and soya bean) the report covers 22 key performance indicators divided into five categories: Research and Development, Industry Competitiveness, Seed Policy and Regulations, Institutional Support, and Service to Smallholder Farmers. We conclude that Nigeria’s formal seed sector is in the early growth stage of development, characterized by, among other factors, established breeding programs and evolving seed policy environments. Seed companies produce and sell a limited range of staple crops and government entities and non-governmental organizations continue to play a significant role. While the National Agricultural Research Institutes continue to be a major source of basic seed in Nigeria, the Consultative Group on International Agricultural Research (CGIAR) centers and companies that specialize in basic seed production were prominent in 2019, contributing to the availability of basic seed being rated highly by seed companies. This is an indication that the sources of basic seed are responding adequately to the needs of seed companies. The government’s efforts to enforce seed policies are impressive but could be improved by reducing the cost and length of the variety release process. In addition to these highlights, the report discusses many positive developments as well as areas for improvement in Nigeria’s formal seed sector.