Given the increasing global focus on corporate governance in the last two to three decades, this study examines the influence of corporate governance structure (board characteristics and ownership structure) and governance disclosure practices on earnings management in Nigerian financial service firms from 2014 to 2023. This study employed a longitudinal research design using panel data from 35 listed financial service firms. From the panel regression analysis, the study utilises the fixed effect model to assess the relationship between corporate governance structures and governance disclosures on earnings management (which is proxied by the Modified Jones Model). The findings revealed that governance disclosure, board gender diversity, leverage and asset growth had significant and negative effects on earnings management. In contrast, CEO gender diversity and firm size significantly and positively affected earnings management. The study therefore revealed that corporate governance disclosure plays a significant role in reducing earnings management by enhancing transparency, accountability, and ethical oversight within Nigerian financial service firms. The study recommends amongst other things that financial service firms should strengthen their governance disclosures and increase female representation on boards to mitigate earnings manipulation and enhance financial integrity.