Carbon tax policies have been widely adopted as instruments for climate change mitigation; however, their implementation in developing countries continues to face significant structural and political challenges. This study aims to analyze the influence of per capita carbon emissions and tax revenue on carbon tax rates in ten developing countries during the period 2021–2023. Utilizing a panel data regression approach with fixed effects models, this research examines the causal relationship between environmental and fiscal factors and the determination of carbon tax rates. The estimation results reveal that per capita carbon emissions have a negative and statistically significant effect on carbon tax rates, with a coefficient of −6.09 (p < 0.01). This finding indicates that countries with higher emission levels tend to impose lower carbon tax rates, possibly due to domestic political pressures and economic dependence on emission-intensive sectors. In contrast, tax revenue as a percentage of Gross Domestic Product (GDP) does not exhibit a significant effect on carbon tax rates (p > 0.05), suggesting that fiscal considerations are not yet a primary determinant in the design of carbon tax policies in developing economies. The policy implications of this study highlight the need for more progressive and integrated carbon tax reforms aligned with sustainable development agendas, particularly in support of Sustainable Development Goal (SDG) 13. This study contributes novel empirical evidence to the green fiscal literature in developing countries and offers strategic recommendations for policymakers to optimize the role of carbon taxation in global emissions reduction efforts.