For a study, researchers sought to examine whether there were any differences between males and females in the longitudinal bidirectional linkages between changes in sleep quality and 2 measures of internalizing issues, depression, and anxiety symptoms. A total of 570 early adolescents (58.6% female; Mage=12.43 years, SD=0.66 at Time 1) were tested 4 times over 1.5 years. The bidirectional relationships between sleep quality and depressed and anxious symptoms were hypothesized and tested using cross-lagged panel models; multigroup tests were performed to test for sex differences. Sleep quality and variations in sleep quality over time were negatively linked with changes in depressed and anxious symptoms over time, and vice versa. There was no difference in these relationships between male and female early adolescents. The study’s findings showed that the link between poor sleep quality and depression and anxiety symptoms was likely bidirectional and consistently linked. Clinicians may think about both issues to help with case conceptualization and therapy.