This study examines the impact of power sector reforms on energy poverty in Nigeria between 1990 and 2023, using electricity access and electricity consumption per capita as key indicators. Employing interrupted time-series analysis, the study assesses both immediate and long-term reform effects following the 2005 Electric Power Sector Reform Act. The results show that electricity access declined immediately after reforms and continued on a negative trajectory, while electricity consumption per capita increased gradually in the post-reform period. Population density positively influenced outcomes, whereas urbanisation showed mixed effects. These findings suggest that reforms improved electricity use among connected users but failed to achieve universal access, highlighting the need for targeted and inclusive energy policies.