<p>In the context of an action-research project in Madrid focusing on sociolinguistic inequalities, this paper presents one of the tools used to prompt critical reflection and discussion on sociolinguistic inequalities and agency amongst higher education students: The questionnaire of critical sociolinguistic incidents. The questionnaire presents experiences drawn from previous ethnographic work that cover situations of misrecognition and unequal distribution of linguistic resources among speakers of minority languages, varieties of Spanish, and the presence of English at Spanish universities. For each critical incident, participant students were presented with multiple-choice answers that suggested possible reactions or opinions, offering different alternatives of agency. The questionnaire of sociolinguistic critical incidents served three main goals: To ask participants to react to lived situations of inequality, to trigger reflection on the agency of speakers, and to assess the impact of the project’s interventions. To assess this impact, the students answered the questionnaire twice, at the beginning and at the end of the semester, in intervention and control groups. Results indicate a shift towards increased agency following the project’s interventions. This research indicates that an ethnography-based questionnaire an effective tool to help students reflect on their linguistic resources, the sociolinguistic order in the university and their own agency in changing this order.</p>