Objective: To evaluate group differences in social adjustment in survivors of pediatric ALL compared to survivor siblings, and controls; identify disease-related predictors of social adjustment in survivors; and explore whether executive functioning explained differences in social adjustment across groups and between disease-related predictors. Methods: Survivors of pediatric ALL (n=38, average age at diagnosis=4.27 years [SD=1.97]; average time off treatment=4.83 years [SD=1.52]), one sibling (if available, n=20), and one parent from each family were recruited from a long-term survivor clinic. Healthy age- and sex-matched controls (n=38) and one parent from each family were recruited from the community. Parents completed the Behavioral Assessment System for Children, Parent Rating Scale (BASC-3) Social Withdrawal subscale as a measure of social adjustment and the Behavior Rating Inventory of Executive Functions (BRIEF-2) as a measure of executive function for each of their children. Results: Parents reported that survivors had significantly worse social adjustment compared to controls (b=6.34, p=.004), but not survivor siblings. Among survivors, greater time off treatment (b=2.06, p=.058) and poorer executive functioning (b=0.42, p=.006) were associated with worse social adjustment. Executive function did not mediate differences in social withdrawal between survivors and controls or the relationship between time off treatment and social withdrawal among survivors. Conclusions: Survivors of pediatric ALL presenting to follow-up programs should be screened for difficulties with social adjustment. Future research should examine treatment- and non-treatment-related factors contributing to poorer social outcomes.