Purpose This study aims to investigate the relationship between carbon risk and tax avoidance practices among American firms. Design/methodology/approach The research examines 854 American firms over the period from 2015 to 2021. A two-stage least squares regression technique with instrumental variables is used to address potential endogeneity concerns. Findings The study shows that an increase in carbon risk is associated with higher tax avoidance, particularly through Scope 1 and Scope 2 emissions. These findings are robust across various metrics used to measure carbon risk and align with the insights derived from agency theory. Research limitations/implications Although focusing on American firms provides a consistent regulatory context, it may limit the generalizability of findings to other contexts. The study’s implications suggest that policymakers and managers should consider the interplay between environmental and tax policies in their decision-making processes. Originality/value This study contributes to the literature by extending the understanding of determinants of corporate tax avoidance by introducing carbon risk as a significant factor. The results provide valuable insights for stakeholders into the evolving dynamics of corporate environmental and fiscal responsibilities.