This study examined a sample of 581 teachers from 60 diverse preschools, utilizing the Preschool Teacher Motivation Questionnaire, the Preschool Teacher Emotional Competence Questionnaire, and the Perceived Social Support Scale. The findings indicated that (a) preschool teachers’ autonomous motivation (M = 13.23, SD = 16.22) and perceived social support (M = 66.93, SD = 11.44) were above the median level, while emotional competence (M = 75.32, SD = 10.02) was at a medium-high level, with all dimension scores exceeding the theoretical median; (b) perceived social support was significantly and positively correlated with autonomous motivation; (c) emotional competence significantly and positively predicted autonomous motivation; and (d) emotional competence fully mediated the relationship between perceived social support and autonomous motivation. These results underscore the importance of emotional competence and social support in fostering teachers’ autonomous motivation. Accordingly, this study recommends implementing strategies that target the development of emotional competence and the provision of adequate social support to effectively motivate preschool teachers.