This study examined the associations between children's and adolescents' autistic-like social deficits and school and social adjustment as well as the moderating roles of age and gender in these associations. The sample consisted of 1321 students (48.7% boys) in Grade 1 to Grade 8 from northern Taiwan. Children's and adolescents' autistic-like social deficits were assessed using the Social Responsiveness Scale (SRS), and their school and social adjustment (i.e., academic performance, negative attitudes toward schoolwork/teachers/classmates, behavioral problems at schools, negative peer relationships, and problems with peers) were assessed using the Social Adjustment Inventory for Children and Adolescents (SAICA). Both measures were completed by the mothers of the participants. Results from the linear mixed models demonstrated that autistic-like social deficits were associated with poor academic performance, negative attitudes toward schoolwork, teachers, and classmates, behavioral problems at schools, negative peer relationships, and problematic peer interactions. Moreover, gender and/or age moderated the associations between autistic-like social deficits and school and social adjustment problems. For example, autistic-like social deficits were more strongly related to negative school attitude, school social problems, and negative peer relationships in boys than in girls. Further, autistic-like social deficits were more strongly related to problems with peers in older girls than in older boys or younger children (regardless of gender). In conclusion, the present study suggests that autistic-like social deficits may place children and adolescents at increased risk for social and school maladjustment and that the extent of maladjustment may vary with the child's age and gender and the domains of adjustment under discussion. (Contains 4 tables and 1 figure.)