School bullying is associated with externalizing and internalizing problems, but little is known about whether reading difficulties also play a part. We asked how, in Grades 1 and 2, word reading skills and externalizing/internalizing problems predict the degree to which students are involved in bullying in Grade 3. Using a sample of 480 Finnish children (M age = 7 years 2 months at the beginning of the study), developmental profiles were identified using mixture modeling based on reading skills, as well as externalizing and internalizing problems. In Grade 3, one fifth of the students were involved in bullying as victims, bullies, or bully/victims. Poor readers with externalizing/internalizing problems were most involved as bullies and bully/victims but not as victims. Average readers with externalizing/internalizing problems were also involved in bullying, whereas students with only reading difficulties were not. Skilled readers displayed little externalizing/internalizing problems and were not involved in bullying.