Background: Nondrug treatments are potentially beneficial for cancer patients. However, the effect of sleep on cancer-related fatigue (CRF) and quality of life (QOL) in cancer patients remains unclear. We conducted a meta-analysis of randomized controlled trials to examine the efficacy of sleep in cancer patients undergoing treatment., Methods: The PubMed, Ovid, Embase, Cochrane Central Register of Controlled Trials, and China National Knowledge Infrastructure databases were searched to identify suitable studies. Stata 15.0 software was used for statistical analyses. Sensitivity analyses were conducted. Fourteen studies (6 in English and 8 in Chinese) involving 1151 patients were included in the meta-analysis. Ten, five, and six studies that assessed the effects of sleep on CRF, QOL, and quality of sleep, respectively, in cancer patients undergoing treatment were identified., Results: Sleep interventions significantly affected overall CRF (standardized mean difference (SMD) = -1.52, P < 0.01), overall QOL (SMD = 1.20, P < 0.01), physical fatigue (SMD = -0.66, P < 0.01), cognitive fatigue (SMD = -0.38, P = 0.015), and physical function (SMD = 0.64, P < 0.01). Comprehensive intervention measures focusing on sleep, sleep nondrug interventions, and interventions for ≥3 or <3 months affect CRF. However, no significant effects on emotional fatigue, emotional function, perpetual fatigue, depression, or quality of sleep were observed., Conclusions: Comprehensive interventions focusing on sleep are helpful for CRF. Sleep interventions may only affect physiological function and have no effect on emotional function, perpetual function, or sleep quality. Future research should focus on how to combine sleep interventions with psychological, social, cognitive, and emotional interventions and provide targeted comprehensive nursing measures to better improve CRF, sleep quality, and QOL., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)