The integration of digital governance and e-government transformation has become a cornerstone of public administration reform globally, particularly in improving efficiency, transparency, and accountability in public service delivery. This study examines the impact of digital governance initiatives in Nigeria, focusing on their role in enhancing efficiency, promoting accountability, and identifying key challenges that hinder their effectiveness. The study adopted the Technology–Organization–Environment (TOE) framework as its theoretical foundation. Using a descriptive survey design, data were collected from 300 respondents drawn from three key federal ministries and citizens interacting with e-government platforms. Quantitative data were analysed using descriptive statistics, Chi-square tests, Pearson’s correlation, and multiple regression, while qualitative insights were obtained through key informant interviews. The findings reveal that digital governance initiatives have significantly improved efficiency and transparency, particularly through platforms such as the Treasury Single Account (TSA), Integrated Payroll and Personnel Information System (IPPIS), and Government Integrated Financial Management Information System (GIFMIS). However, the results also show that systemic barriers including weak ICT infrastructure, low digital literacy, and entrenched corruption continue to undermine full-scale transformation. The study concludes that while Nigeria has made notable progress, sustainable digital governance requires stronger infrastructure investment, enhanced digital literacy, policy consistency, and deeper citizen inclusiveness.