Very little qualitative research has been carried out about the experiences of educators who deliver mathematics evidence-based teaching programmes to autistic students. Using a semi-structured format, we interviewed ten educators who had been delivering the Teaching Early Numeracy to Children with Developmental Disabilities (TEN-DD) programme for eight months with autistic students in a special school setting. Reflexive thematic analysis findings indicated that taking part in the numeracy intervention was a valuable experience for both the educators and their students. There was initial scepticism about the intervention, but this was transformed to conviction during the implementation period. Educators reported an increased sense of competence in their teaching skills, evident in greater satisfaction and increased self-efficacy. Furthermore, there was a strong interest in continuing to use the numeracy intervention with students. There were also implementation challenges with TEN-DD, including students' challenging behavior. The implications of these findings are discussed.