Objectives: The increasing demand for computing skills has led to a rapid rise in the development of new computer science (CS) curricula, many with the goal of equitably broadening the participation of underrepresented students in CS. While such initiatives are vital, factors outside of the school environment also play a role in influencing students' interests. In this article, we examined the effects of students' perceived parental support on their interest in computer programming and explored the mechanisms through which this effect may have been established as students participated in an introductory CS instructional unit. Participants: This instructional unit was implemented with upper primary (grade 5) school students and was designed to broaden trajectories for participation in CS. The participants in the current study (N = 170) came from six classrooms in two rural schools in the western United States. Study Method: The seven-week instructional unit began with students playing a commercial CS tabletop board game that highlighted fundamental programming concepts and transitioned to having students create their own board game levels in the block-based programming language, Scratch. Further, because the board game could be taken home, the instructional unit offered opportunities to involve the family in school-based CS activities. To investigate the effect of students' perception of parental (specifically father and mother) support on their interest in and self-efficacy to pursue CS, we surveyed students before and after the unit's implementations and explored the structural relationship of the data using structural equation modeling. Results: We present three findings. First, the combined effect of students' perceived mother's and father's support measured prior to the implementation (pre-survey) predicted students' self-efficacy (Standardized Estimate ([beta]) = 0.37, standard error = 0.010, p <0.001) and interest in computer programming (Standardized Estimate ([beta]) = 0.328, standard error = 0.134, p<0.003) measured after the implementation (post-survey). Secondly, the combined effect of perceived mother and father support (Standardized Estimate ([beta]) = 0.132, 95% CI [0.039, 0.399], 99% CI [0.017, 0.542]) on students' interest was mediated by whether or not they took the CS board game home. Conclusions: Our findings indicate that perceived parental support has the potential to play an important role in students' self-efficacy and interest in computer programming and that providing opportunities for students to bring CS artifacts home has the potential to further affect students' interest in computer programming.