Currently, parental involvement research considers parents as individuals, and gives little consideration to them as a collective body, including how, as a group, they might influence each other. This study examined the influence of parent social norms on parents' home reading behaviour with their child. Two quasi-experiments conducted in two elementary schools (N = 124 children) examined the influence of information about the reading behaviour of the majority of other parents. Completion rates of a reading challenge for each class were compared seven months later. Across the two schools, the intervention resulted in significantly more parents completing the reading relative to control classes who did not receive the information (76% vs. 47%). Additionally, a follow-up survey suggested parents did not perceive the social norm information as a persuading factor, despite its clear success as a motivator. Consideration of these findings for schools and future research is offered and discussed.