INTRODUCTION: First aid training is crucial in schools, especially in vulnerable contexts such as Indigenous early childhood education institutions, where a lack of resources may increase the risk of accidents. OBJECTIVE: To evaluate the outcomes of an educational intervention in first aid for teachers and school staff.METHODS: This is a quasi-experimental, non-randomized study with a single group, conducted between May and June 2022. The intervention consisted of workshops that included both theoretical and practical components covering: (1) initial assessment of an unconscious victim; (2) definition of seizure; (3) management of foreign body airway obstruction (FBAO); (4) seizures; (5) chest compressions for infants under one year old; (6) effectiveness of cardiopulmonary resuscitation (CPR); and (7) fainting. A semi-structured questionnaire was administered before and after the training to assess participants’ knowledge.RESULTS: The results showed a significant increase in participants’ knowledge, with the mean questionnaire score increasing from 3.6 (±1.26) to 8.5 (±1.43) after the intervention, according to the McNemar test (p ≤ 0.05).CONCLUSION: Training school personnel in first aid promotes a safer school environment, and the educational intervention proved to be effective, highlighting the need for ongoing training programs.