PurposeThis study aims to explore the determinants (bank-specific, industry-specific and macroeconomic) of income diversification across interest income and non-interest income as well as for non-traditional income sources (non-interest income) from 2004–2005 to 2021–2022.Design/methodology/approachAn unbalanced data set comprising 110 Indian commercial banks with 1480 observations is sampled in this study. Because of the bounded nature of the dependent variables (proxies of income diversification), the panel Tobit regression model is used.FindingsThe findings reveal that income diversification is positively influenced by bank size, technological advancements, cost–income ratio, return on assets, market competition and inflation in the economy. However, the decision to diversify income sources is adversely impacted by the capital ratio, GDP and financial intermediation ratio. Moreover, factors such as asset quality (loan loss provisions) and liquidity ratio do not directly influence the diversification strategies in the Indian banking industry.Practical implicationsThe present study uses an extensive set of variables to provide insights into key factors for bank managers, regulators and policymakers to consider before developing diversification strategies.Originality/valueTo the best of the authors’ knowledge, this is the first study to examine the various bank-specific and macroeconomic determinants that affect income diversification in the Indian banking sector. The current study also investigates new variables such as technological advancements and a market concentration index for measuring competition, which have not been investigated in existing literature concerning bank income diversification in the Indian context.