This analytical study documented the presence of transactions in parent-child engagement within a sample of young children at an elevated likelihood for an eventual diagnosis of autism spectrum disorder (ASD). Specifically, the study examined the establishment of transactional engagement through reciprocal behaviors between parents and their young children at-risk for ASD. In the study sample, established transactional engagement occurred at a higher rate than other levels of engagement. Additionally, transactional engagement had a higher likelihood of being established when parents initiated. Post-hoc analyses revealed possible early markers of ASD within a certain behavior displayed in transactions. This study signifies the initial efforts in identifying transactions within parent-child engagement, and foremost, how transactional engagement is established.