Decisions concerning capital structure are crucial for every business organization as maximization of firm value is a complex task and involves the selection of debt and equity securities in a balanced proportion, keeping in view the different costs and benefits attached to these securities. This empirical study aims to explore the factors that affect the capital structure in Indian firms and to know which capital structure theory--whether the pecking order theory or the trade-off theory--justifies the findings of the study. The investigation is performed using panel data procedures on Indian firms during 2009-2018. The dependent variables used are short-term debt, long-term debt and total debt. Profitability, firm's size, growth rate, tangibility, business risk, interest coverage ratio, non-debt tax shield, tax rate and liquidity are taken as the independent variables. The results suggest that variables such as profitability, firm's size, liquidity, risk and tax rate affect the capital structure of the Indian firms, and short-term debt is found to be an essential financing source of the Indian firms. This study has laid some groundwork to explore the determinants of the capital structure of the Indian firms upon which a more detailed evaluation could be based. [ABSTRACT FROM AUTHOR]