In Nigeria, most citizens between the ages of 20-60 believe that ethnicity is the leading cause of discrimination. The central problem addressed in this study was how ethnic diversity influenced managerial choices in Nigeria. The purpose of this qualitative case study was to explore the role of ethnicity in managerial choices in a Nigerian federal traffic management agency to gain an understanding of how ethnicity influenced managers' recruitment, placement, and promotion of employees. Complexity theory and a consideration of African management practices constituted the conceptual framework. Participants were 11 managers who were recruited from a Nigerian government agency using a combination of purposive and snowball sampling. Data collection occurred through interviews, observation, and government document reviews. Through use of Yin's 5-step process for data analysis, data triangulation, and member checking, 10 themes emerged regarding managers' decisions: (a) federal character principle, (b) merit, (c) ethnicity, (d) influence of godfathers, (e) favoritism, (f) promotion, (g) productivity, (h) morale, (i) frustration, and (j) health challenges. A conclusion was that ethnicity played a role in managerial choices. However, the execution of the current Nigerian law to manage ethnic diversity allowed the alleged discriminatory actions of managers in government agencies. Recommendations included a change in the implementation strategy of the federal character principle to reduce incidences of discriminatory actions in government agencies. This study may contribute to positive social change by providing public service managers the knowledge to create an enlightened and fair public service, free of ethnically induced barriers that have underpinned Nigeria's underdevelopment.