In Environmental Impact Assessment (EIA), the public participation must be incorporated to achieve a more equitable distribution of power. This study is based on the importance of understanding how the relationships between governmental, corporate, and social dimensions involved in an EIA process are established, of understanding how society can participate, and identifying what makes it, in fact, participatory. The objective of this research is to describe and analyze the public participation in EIA process of São Paulo state. The case study was process considered participatory by stakeholders, and the selected one was the Mário Covas Ring Road. The analysis considered the processes until the issuance of the preliminary license. The methodology of this work was divided into two stages. In the first, a survey was used to define the case studies and to identify perceptions of what a participatory case is.From this, the case of the Ring Road was selected. The second stage of the methodology included documentary analysis for the licensing processes with EIA of the selected case, a semi-structured interview with stakeholders involved in the processes, and content analysis.When relevant, the IRAMUTEQ software was also used for textual analysis based on statistics. The results obtained pointed out that the EIA process of the Ring Road was considered participatory because it raised controversies about the justification of the project, the design of the project, about the environmental and urban impacts resulting from its implementation, for involving different actors and for presenting social mobilization organized by the interested parties. In the process, public participation occurred mainly in the involvement of the Environmental State Council (CONSEMA), in the written manifestations of stakeholders, in the publicity of information, in consultation with other bodies linked to the process, and in public hearings. The perception of the stakeholders in the EIA process about public participation demonstrated a strong association with the timing of public hearings. The stakeholders interviewed considered that the EIA process in São Paulo state is good and that participation is essential, but that there is still much to be improved. With this research, it was possible to understand the moments and reasons why an EIA process is considered participatory, the perception of stakeholders about public participation, and to identify possible improvements to involve the public during an EIA process.