The Incredible Years® Helping Preschool Children with Autism (IY-HPCA) program is designed for teachers of children aged 2 to 5 years who have students with autism in their classrooms. The program provides tools to support children with autism. The primary aim of this pilot study is to examine the feasibility of implementing the IY-HPCA intervention among teachers of preschool children (typically aged 2 to 5 years) working in mainstream schools. Specifically, we aim to assess teachers' engagement, acceptability, and satisfaction with the program. Secondarily, we aim to gather preliminary evidence on the program's effectiveness in improving teachers' use of strategies, teacher self-efficacy, and in reducing burnout. We will conduct an exploratory randomized controlled pilot trial. We aim to recruit approximately 40 teachers, and they will be randomly assigned to either an intervention or control group. The intervention consists of six weekly sessions lasting 3 hours each, delivered by clinical psychologists and child psychiatrists specialized in developmental disorders at Hospital Sant Joan de Déu, in Barcelona. Two intervention face-to-face groups will be conducted at Hospital Sant Joan de Déu. Feasibility outcomes include program attendance, acceptability, and satisfaction (assessed using the Incredible Years Teacher Workshop Evaluations and the Teacher Satisfaction Questionnaire), as well as fidelity to the intervention delivery (measured with the Leader Checklist). After the intervention, individual interviews with teachers and group leaders will qualitatively assess satisfaction and experiences with the program. Secondary (effectiveness) outcomes include teachers' use of strategies (Teacher Strategies Questionnaire for Children with Autism), self-efficacy (Teacher Sense of Efficacy Scale), and burnout (Maslach Burnout Inventory-Educators Survey). This study will provide pioneering insights into the implementation of this program within the public mental health and education systems in Spain. This will allow the potential implementation of a wider randomized controlled trial in the future at a larger scale.