In a rapidly evolving world, grit and creativity in Science, Technology, Engineering, and Mathematics (STEM) are crucial attributes for the future development of adolescent students. However, the psychological mechanisms underlying this relationship remains unclear. This study presents a new theoretical framework that explores how STEM-specific grit influences STEM creativity. It also examines the roles of positive psychological traits--such as creative self-efficacy and future time perspective in the STEM domain. A total of 1263 Chinese adolescents in grades 7 to 9 completed measurements of STEM-specific grit, creative self-efficacy, STEM creativity, and future time perspective. The results indicated that STEM-specific grit directly and positively predicted STEM creativity. Furthermore, STEM-specific creative self-efficacy was found to positively mediate the relationship between STEM-specific grit and STEM creativity. Moreover, future time perspective moderated the first half of the mediation model. The findings provide educational guidelines and suggestions for enhancing STEM creativity among adolescent students.