Turnover intention among healthcare professionals remains a major challenge for healthcare organizations because of its implications for employee retention, service quality, and organizational sustainability. Among the factors associated with turnover intention is employees’ perception of an imbalance between the effort they invest in their work and the rewards they receive. Drawing on Siegrist’s Effort-Reward Imbalance (ERI) model, this conceptual paper examines how persistent effort-reward imbalance contributes to turnover intention among Nigerian health workers. The paper argues that excessive job demands coupled with inadequate rewards, including salary, recognition, and career advancement opportunities, can generate psychological strain, job dissatisfaction, counterproductive work behaviours, and ultimately turnover intention. The paper further highlights the practical relevance of the ERI model in explaining employee withdrawal cognitions and emphasizes the need for healthcare managers to establish equitable financial and non-financial reward systems that promote employee commitment and retention. The paper concludes that achieving a better balance between employees’ efforts and organizational rewards is essential for improving workforce stability and supporting the long-term sustainability of Nigeria’s healthcare sector.