In this study, we examined students' experiences regarding precollege engineering curricula, classroom environments, and their experiences with the creative process in two engineering courses offered in a university-based summer enrichment program. Applying provisional and open coding to interview data from 16 participants, an Input-Process-Outcome Model of Collaborative Creativity (IPOCC model) was developed. The IPOCC model expands the 4P model of creativity to incorporate more collaborative contexts. The IPOCC model suggests that in K-12 collaborative practice, creativity involves group-level considerations in addition to individual-level components. The IPOCC model offers insights for educators in terms of input components, group processes, and mediating factors that can facilitate learners' engagement in creative teamwork. The findings of this study indicated that a combination of challenging tasks, open-ended problems, and student teamwork provides a rich environment for learners' engagement to think creatively.