Throughout this critical literature review, we present some theoretical and ethical challenges that the empirical use of voice poses to the knowledge and the development of public policies on inclusion in education. To this aim, we reviewed 31 studies that focus on voice, such as it is defined by the social model of disability, as a unit of analysis for inclusive practices in different educational scenarios. We found that voice is a synonym for discourse, and it describes three empirical routes: voice that points out social barriers, voice that expresses attitudes and beliefs, and voice that copes with stigma. Drawing upon our findings, we justified the need for producing knowledge for inclusion from another onto-epistemological perspective. As alternative, we suggested that new materialisms allow us to interrogate the ideas of the human and the difference underneath the social model of disability, given its modern ontological roots. In this direction, we redefined voice to recognize as such to every minuscule difference expressed by each alive materiality. Then, we reflected on the possibilities of creating knowledge that leads to a non-deterministic understanding of the difference and the human, and encourages the becoming of new discourses, practices, and public policies for inclusion in education.