Background: Autism spectrum disorder is one of the most common disabilities in schools, with up to 50% of such children displaying behaviours that challenge, bringing about demanding teaching circumstances and a negative impact on educators' well-being. Strength-based interventions has not formally been used in autistic classrooms in South Africa and research regarding the topic is limited. Aim: To determine the effect of a strength-based intervention on educators' perception of their own well-being, self-efficacy and the behaviour of autistic learners in their class. Setting: This study was carried out in one autism-specific school in Nelson Mandela Bay of South Africa that met the specific inclusion criteria. Methods: This exploratory study used a pre-experimental group design with three pre-intervention -post-intervention outcome measures to determine the effect of an intervention to support educators. The researcher presented a one-day training programme on a 6-week character strength intervention to use and implement in the autistic classroom. Results: A few statistically significant changes were found of learners' behaviours that challenged, but none for educators' well-being and self-efficacy. Verbal aggression significantly decreased both in frequency and severity. Behaviours that declined significantly in severity were physical aggression, disruption, destruction and manipulative, deceitful or non-compliant behaviour. Conclusion: The research showed educators' stronger focus on strengths made a difference in learners' behaviour that challenge. The exploratory study shows some positive results, which indicate a larger study can be undertaken with some changes. Contribution: The outcomes contribute to the character strengths and positive education theoretical frameworks and can be relevant to support autistic learners' behaviours.