Previous studies have indicated that situational factors can influence students' creativity. However, no studies have specifically examined the relationship between classroom goal structures and student creativity during real classroom activities. For this study, we recruited 232 seventh-grade students from Taipei City and randomly divided them into the following three classroom goal structure groups at the start of the semester: an enhanced group with a mastery classroom goal structure, an enhanced group with a multiple (mastery and performance) classroom goal structure and a control group. Before receiving the experimental manipulation, the students' level of creativity showed no significant differences. After six weeks, the students in the enhanced groups with mastery classroom goal structure and multiple classroom goal structure exhibited superior fluency, flexibility and creativity compared to those in the control group. However, the creativity of the students in the enhanced groups with mastery classroom goal structure and multiple classroom goal structure showed no significant difference. This indicates that the mastery classroom goal structure itself can sufficiently enhance students' creativity. The results of this study support the existence of a causal relationship between classroom goal structures and student creativity. When teachers develop an appropriate learning climate in classrooms with an emphasis on mastery goals, students' creativity and creative expression can be stimulated. We also discuss the theoretical and extendable implications of this study based on the results.