PurposeThis study investigates the combined influence of corporate governance (CG) and debt maturity (DM) on the investment inefficiency among non-financial 506 NSE-listed firms in India between 2009 and 2022. Additionally, this study also investigates the moderating effect of short-term debt (STD) maturity concerning the relationship between CG and investment inefficiency.Design/methodology/approachUtilizing the residuals extracted from the Biddle et al. (2009) investment model, three different forms of investment inefficiency (investment inefficiency, overinvestment and underinvestment) were measured. To measure the internal governance of firms, a new corporate governance index (CGI) was developed using 65 new governance stipulations, whereas STD was measured as short-term debt divided by total debt. Interaction effects between CG and DM were also estimated. Employing CGI and STD along with firm-specific control variables, many pooled regression models were estimated. Endogeneity issues were addressed through two-stage least squares. Robustness checks were also conducted using the two-step system GMM, alternative measures of dependent and independent variables.FindingsThe findings demonstrate that higher CG and shortened DM increase investment efficiency. This evidence implies that firm-level governance and short-term debt reduce information asymmetry and increase management oversight. Additionally, the evidence suggested that shortened DM and CG complement one another to increase investment efficiency, suggesting companies that utilize STD to a greater (lesser) extent demonstrate a greater (lesser) impact of CG in reducing investment inefficiency.Practical implicationsThis work first advocates the establishment and implementation of robust corporate governance mechanisms to control agency conflicts, moral hazard, adverse selection and limit opportunistic behavior of managers for improving investment efficiency. Second, since interaction effects suggest a complementarity between CG and DM, it is advocated that STDs can be used to achieve optimal investment choices to control moral hazards and adverse selection and discourage suboptimal investment levels.Originality/valueThis work provides new evidence concerning the effects of CG and DM on various forms of corporate investment efficiency (investment inefficiency, overinvestment and underinvestment, using alternate measures) in an emerging economy like India having a unique institutional framework and macroeconomic environment using a newly developed firm-specific CG index for a large sample of companies using recent data.