Parent-child co-participation has often been correlated with physical activity engagement levels. However, both new research and anecdotal evidence suggest that parent-child sport co-participation may provide developmental benefits for both parents and their children beyond simple rates of engagement. The aims of this scoping review were twofold: first, to gather the available research on parent-child co-participation in the sport context and identify how co-participation has been conceptualized in the literature, and second, to discuss the contexts in which parent-child co-participation have been investigated. Through this review, we found that co-participation has most often been conceptualized as either a predictor of physical activity or a one-dimensional outcome variable. A small number of studies have examined co-participation as a developmental process. Future research recommendations include examining the co-participation in greater detail as a process, with the intent to further understand the developmental contexts of these sport and relationship environments.