This article examines Post-Harvest Losses in East African Agriculture: Scale, Causes, and Reduction Strategies with a focused emphasis on Nigeria within the field of Sociology. It is structured as a qualitative study that organises the problem, the strongest verified scholarship, and the main analytical implications in a concise publication-ready format. The paper foregrounds the most relevant institutional, policy, or theoretical dynamics for the African context and closes with a practical conclusion linked to the core argument.