Examined relation between puberty and adjustment problems in 7th through 10th-grade males. Found that, compared with less physically developed peers, more physically developed boys in grade 7 manifested more externalized hostile feelings and internalized distress in grades 8-10. Pubertal timing related to distress and hostility, even when controlled for grade 7 maladjustment symptoms and concurrent stressful life events. (Author/KB)