Tax on the Circulation of Goods and Services (ICMS) Ecological, a tax strategy for environmental preservation, redistributes the existing tax, encouraging sustainable practices.This research seeks to understand how the Ecological ICMS tax approach impacts the revenues of municipalities in the State of Tocantins.The question addressed in the research is: How do the tax aspects of the Ecological ICMS equitably impact the revenues of municipalities in the State of Tocantins, considering the definition of tax rates and the link to specific environmental