The Social ABCs is an evidence-based, developmentally informed, caregiver-mediated behavioural intervention for toddlers with suspected or confirmed Autism Spectrum Disorder (ASD). It is based on principles of Pivotal Response Treatment (PRT, grounded in Applied Behaviour Analysis), and responsive parenting. The two key targets of this program are functional verbal communication and positive caregiver-child affect sharing. This intervention takes place in the context of play and daily routines, and in all contexts is made to be fun.