The purpose of the present study was to assess sluggish cognitive tempo (SCT) behavioral symptoms among pediatric survivors of acute lymphoblastic leukemia (ALL) and to determine the relationship of these behaviors with cognitive late effects. Methods ALL survivors (n = 80) and a sibling control group (n = 19) were administered intelligence (IQ) testing, achievement testing and SCT behavioral items. Group differences (patients vs. siblings) were examined on the SCT behaviors and partial correlations were conducted to explore the relationship of the SCT behaviors with IQ and achievement, while controlling for age at treatment and time since treatment. Results ALL survivors exhibited significantly more SCT symptoms than the sibling control group and increased SCT symptoms were associated with lower IQ and achievement scores. Conclusions ALL survivors are vulnerable to SCT symptoms and these behaviors are associated with cognitive late effects. SCT symptoms may represent a behavioral component of cognitive late effects.