In recent decades, with the rapid development of the knowledge economy and science, countries have embraced technical innovation and have gradually increased investment in research and development (R&D). A vast literature indicates that the relationship between R&D and firm performance is highly complex. The evidence suggests that R&D positively influences firm performance, yet findings on the process by which this happens are mixed. Rigorous analyses are required on how R&D investments affect energy consumption. This study explores the impact of R&D investment on the performance and energy consumption of 476 firms in Ethiopia by employing a combination of fixed-effect, propensity score matching, and endogenous treatment effect estimation methods. The empirical results reveal that investment in R&D positively influences both innovation and long-term financial performance but negatively impacts short-term financial performance and energy consumption. The results also show that the impacts of R&D activities vary significantly across different categories of firms, confirming that heterogeneity may be an issue among the firms considered. The results also indicate that the availability of credit is a more important moderating factor in the relationship between R&D investment and firm performance than the legal system is. These results have important implications for firms with growing R&D operations, especially those in developing countries such as Ethiopia. Ethiopian firms should invest more in R&D activities, such as in fundamental and applied research, to improve performance and enhance competitiveness.