The banking and financial services sector in India has witnessed rapid growth, with Non-Banking Financial Companies (NBFCs) playing a pivotal role in providing credit to underserved segments such as MSMEs, rural households, and small entrepreneurs. This study examines the financial sustainability of NBFCs in Tiruchirappalli, Tamil Nadu, by analyzing key financial indicators including profitability, liquidity, asset quality, and capital adequacy over the period 2020–2024. The study is based on secondary data collected from annual reports and regulatory publications. Analytical tools including ratio analysis and correlation analysis are employed. The findings reveal that profitability, asset quality, and capital adequacy have a significant impact on financial sustainability, whereas liquidity exhibits a moderate influence. The study highlights the importance of effective risk management, regulatory compliance, and technological adoption in ensuring the long-term sustainability of NBFCs.