Students’ perceived competencies may reflect dispositions to trigger and enhance engagement acts and promote engagement benefits. Although perceived competencies and engagement acts are significant resources in STEM learning, their relationships remain unclear. Accordingly, we applied the transactional model of engagement (TME) to examine these associations, focusing on how emotional and cognitive engagement affect the mediating effect of perceived digital inquiry on perceived creativity. The participants were 305 secondary school STEM learners in Hong Kong. Mediation analyses showed that emotional engagement mediated the positive relationship between perceived digital inquiry and creativity, whereas cognitive engagement had no such mediating effect.