Previous research indicates that indices of happiness (IOH) can provide useful information regarding the social validity of behavioural interventions. One way to measure happiness might be to simply ask the participants how they are feeling. However, when focusing on populations lacking the skills to effectively communicate their internal emotional states, such as young children diagnosed with autism spectrum disorder (ASD), indices other than verbal self-reports are necessary. Monitoring observable behaviours likely correlated with states of happiness can be one method. In this study, IOH were measured in two young children diagnosed with ASD, in a naturalistic parent-implemented play-based shaping intervention to improve eye contact. IOH were measured in three different social play activities per child. The parents were trained and supervised via telehealth. IOH were individualized and operationally defined for each child, based upon parent responses to a pre-intervention questionnaire, and monitored via video recordings. Interobserver agreement was 92% (range 88-100%). The results, as measured by the observed pre and post intervention IOH, as well as parents' self-reports, indicate a high degree of social validity. This study was a collaboration between Stockholm University and Behavior Momentum India, conducted during the COVID-19 pandemic.