This study aims to explore how the capital structure affects the financial performance of healthcare companies listed on the Nigerian Stock Exchange (NSE) from 2012 to 2021. Capital structure which considers how a company combine its mix of equity and debt in financing its business is important to its overall operations and growth. To conduct this research, eight healthcare firms listed on the NSE were deliberately chosen. The study examined the financial data of various firms, through their annual reports. The data included short-term and long-term debts, equity (the value of a company's shares), return on equity, and size. The study used correlation and regression for its analysis. The results showed that short-term debt, long-term debt, and equity had a negative but significant relationship with return on equity. However, the size of the company had a positive and significant relationship with return on equity. Based on the findings, the study recommends that healthcare firms should consider using long-term debts to increase the time to repay the borrowed capital and generate more profit.