The term social participation is widely used and has various meanings in different contexts. This article aims to enhance the understanding of social participation in science museums. The research was conducted using a cultural-historical perspective in six steps: (1) survey to identify the meanings attributed to the term social participation and actions considered participatory in Brazilian science museums; (2) content analysis with coding; (3) literature review on social participation meanings; (4) analysis and revision of categories; (5) survey for educators from Brazilian science museums to validate the dimensions emerged in the first survey; (6) final analysis: synthesis of the dimensions of social participation and proposal of a model. As a result, we recognized five dimensions that contribute to the concept of social participation in science museums: "access"--removing barriers to participation that promote social exclusion; "identity and diversity"--creating a multicultural space that examines and redefines oppressive and unequal relationships; "co-creation and authorship"--fostering different forms of collaboration with audiences; "interaction and dialogue"--expanding opportunities for interaction with exhibitions; "exercise of citizenship"--empowering the audiences to participate in social change. Although these dimensions provide insights into social participation in science museums, limitations exist. These dimensions can contribute to developing museum practices that dialogue with communities and strengthen social participation in science museums.