Study Objectives: Sleep problems are common in children and adolescents and can aggravate comorbid disorders. This meta-analysis examined the effect of cognitive and behavioral sleep interventions (with four or more treatment sessions) from randomized controlled trials on school-age children and adolescents. Methods: In a systematic literature search, six randomized controlled trials were identified (n = 528; mean age = 14.6 years; female = 63%) that reported total sleep time (TST), sleep onset latency (SOL), wake after sleep onset, and daytime sleepiness from ratings and actigraphy. Results: After intervention, no effect was seen on self-reported TST, but when measured with actigraphy, an effect favoring the intervention group was observed (+11.47 minutes, P = .05). SOL decreased in the intervention group compared to the control group after intervention as measured by both sleep diaries (−9.31 minutes, P = .007) and actigraphy (−19.48 minutes, P < .0001). Effect sizes ranged from small to large. No effect was found for wake after sleep onset or daytime sleepiness. Short-term (4 to 8 weeks) follow-up data from four studies indicated maintained positive effects on SOL: sleep diaries −15.85 minutes (P = .01) and actigraphy −23.67 minutes (P < .0001). At follow-up, the effects on wake after sleep onset from ratings (−14.41 minutes, P = .001) and actigraphy (−7.54 minutes, P = .01) were significant, favoring the intervention group (moderate to large effect sizes). No effect on TST was indicated. Conclusions: Cognitive and behavioral sleep interventions are indicated to improve sleep in school-age children and adolescents. However, because treatment protocols were heterogeneous and risk of bias high, results should be interpreted with caution. Large and rigorous trials are needed.