Several theories have proposed that emotional separation and parental trust in parent–adolescent relationships have significant roles on adolescent autonomy development. Although these associations have been demonstrated among middle-to-late adolescents, no empirical study has tested them among children and early adolescents. The present study aimed to investigate the associations of emotional separation and parental trust with diverseindicators of behavioral autonomy, including communication behaviors with parents (i.e., individuality-oriented and connectedness-oriented communications) and behaviors at homeand school (i.e., waking up at regular times, doing homework, reviewing learning contents, and observing rules at school), among children and early adolescents. Elementary school students (n = 857; 49.59% girls; Mage = 10.80) and junior high school students (n = 518; 47.68% girls; Mage = 13.56) completed the questionnaires. Emotional separation was positively associated with individuality-oriented communication and negatively associated with connectedness-oriented communications, doing homework, and reviewing learning contents. Meanwhile, parental trust was positively related to both individuality-oriented and connectedness-oriented communications, waking up at regular times, doing homework, reviewing learning contents, and observing rules at school. These results indicate that emotional separation may promote one’s firm sense of self differing from his/her parents; however, emotional separation generally works negatively in autonomy development, whereas parental trust works positively. Overall, the present study provides further understandings of the roles of emotional separation and parental trust on autonomy in childhood and early adolescence, which have not been examined to date.