Abstract: This study collected data on classroom learning engagement, need satisfaction, and need frustration from 213 undergraduate students at three universities in southwestern China, measured at both the beginning and end of the semester. Based on cluster analysis of students’ classroom learning engagement, the study compared changes in need satisfaction and need frustration across groups over the semester. Five distinct engagement trajectory clusters were identified: stable-high, stable-low, high-ascending, medium-ascending, and declining. For two groups with similar initial engagement levels, high emotional engagement at the beginning of the semester facilitated entry into an upward spiral of learning. Conversely, high levels of need frustration at the beginning of the semester tended to drive students into a downward spiral, leading to declining engagement or plateauing at a low level. Finally, to improve students’ emotional engagement and reduce need frustration, university teachers are advised to prioritize building a positive classroom climate and to implement autonomy-supportive teaching behaviors.