This mixed-methods case study examines parental motivation for participation in a Canadian university-based STEM outreach event. Parents responded to a post-event questionnaire that was followed by individual interviews. The quantitative part revealed how and why parents engaged with their children's STEM education. Surprisingly, neither university admission requirements nor STEM-related job opportunities were top motivating factors. The qualitative part indicated that some parents found it challenging to connect their children's learning experience in school with the government-mandated curriculum or with their own experiences. Most interviewees were satisfied with their children's STEM education and considered family support crucial in this process. [For "Parental Engagement in Children's STEM Education. Part I: Meta-Analysis of the Literature," see EJ1227628.]