Autistic children who use minimal functional speech to communicate may benefit from augmentative and alternative communication (AAC) systems. The Picture Exchange Communication System (PECS) is a picture-based system that may be helpful to some autistic children in acquiring a symbolic mode of communication. However, there is evidence that autistic children who access PECS differ substantially in their rate of mastery. It has been suggested that autistic children's object exploration may moderate their response to PECS. The aim of the study was to investigate whether autistic children's object exploration at baseline capability moderated the level of PECS mastered. A prospective cohort study was used, involving 31 autistic children who attended a community-based early intervention program between 2021 and 2022. All participants in the study received support to use PECS within activities over a 12-week period. The primary outcome measure was the change in PECS phases mastered after 12 weeks of implementation. The moderators studied were object exploration, chronological age, cognition, and autistic characteristics at the time of implementation. Using ordinal logistic regression, a model examining the children's mastery of PECS was not statically significant, X2(4) = 3.893 p = 0.421 with none of object exploration, chronological age, cognition, and autistic characteristics found to be a statistically significant moderator. The findings showed that children's object exploration did not moderate the number of phases they mastered over a 12-week period. Further studies are needed to establish other factors that may explain variability in PECS outcomes.