Digital games can be used as educational tools for tackling structural inequalities and promoting social justice. Designing games with these purposes is a complex task that requires a myriad of combined expertise, including games' mechanics, software development, educational game design, pedagogy and knowledge of the educational topic (which can target specific social issues). Democratising the design of educational games is used to increase the agency and participation of diverse and novice groups throughout design processes and can be used to improve the efficiency of such games as it directly leads to the inclusion of broad voices, knowledge, experiences and perspectives. This research adopted a Design-Based Research methodology to create, evaluate and validate 13 design principles to democratise the design of educational games for social change. Three research phases were implemented in turn: a preliminary, prototyping and evaluation phase. The preliminary phase was based on creating these principles by grounding them on fundamentals of Critical Pedagogy, a theory of education which presents pedagogical techniques to accelerate learning, engagement and social change. The prototyping phase was based on conducting semi-structured interviews to assess and improve these principles with educational and game design experts. During the evaluation phase, these principles were applied and evaluated during two weekend-long game design events, called Game Jams. These were open to anyone interested in creating a digital game to raise awareness of gender inequalities, and 13 of the 23 participants (57%) had no previous experience in game design. This research presents theoretical and practical contributions related to how to democratise educational game design for social change. It evidenced the relevance of facilitating design principles that address "what" could be done to trigger learning in games; "why" this learning could be facilitated, from both pedagogical and gaming perspectives; and "how" to implement these principles into educational games.