Background: Prospective longitudinal studies of infant siblings of children with autism spectrum disorder (ASD) play an important role in advancing our knowledge about early developmental pathways in ASD. Despite this clear benefit, currently little is known about potential risks or disadvantages for participating families. As a first step in addressing this issue, we asked parents about their experiences from participating in an infant sibling study. Method: Eighty-eight families responded to a questionnaire examining parents’ experiences from participating in an infant sibling study. The questions assessed parents’ satisfaction with the study, the child’s perceived satisfaction, and the parents’ motivation for participating. The study included parents of two groups, (1) infants with an older sibling diagnosed with ASD (HR, high risk, n = 43) and (2) infants with no familial history of ASD (LR, low risk, n = 21). Results: The results indicated that parents are generally positive about study participation and few disadvantages were reported. This pattern was mirrored when splitting parents’ responses into the two groups. There was no indication for group differences between parents of infants at high risk and low risk for ASD. Conclusion: Our findings present a first step into understanding parents’ experiences from participating in an infant sibling study. Most parents were satisfied with participation in the study and only few disadvantages were reported. Our results have implications for ethical discussions about benefits and risks regarding infant sibling studies in various fields.