Previous studies demonstrate that cyberbullying perpetration and sleep quality likely have vital linkages to each other and to emotional distress. In this article, we examine the bidirectional association between cyberbullying perpetration, sleep quality, and emotional distress in a longitudinal data set with two waves of data collection (T1 and T2, 8 months apart). The participants included 661 Chinese junior high school students (n = 661; mean age, 14.02; 61.4% male) who filled out the Revised Cyber Bullying Inventory-Cyberbullying Subscale, Pittsburgh Sleep Quality Index, and Depression Anxiety Stress Scales. Results revealed that cyberbullying and sleep quality would predict each other over time, and significant bidirectional relationships were found between sleep quality and emotional distress across T1 and T2. Cyberbullying at T1 would not predict the emotional distress at T2, whereas emotional distress at T1 was associated with cyberbullying at T2.