Purpose – Evidence supporting complementary and integrative medicine (CIM) for improving cancer-related fatigue (CRF) is still fragmented. This study therefore critically appraised all the systematic reviews (SRs) regarding the effectiveness of CIM in mitigating CRF in adults. Methods – A systematic review of SRs and a meta-analysis were conducted in 4 databases. The effect sizes of the included SRs were quantitatively pooled (standardized mean difference [SMD]; 95% CI) using a random-effects model. Heterogeneity was tested by using χ2 (Q) tests and I² statistics. Findings – Twenty-two SRs met the inclusion criteria, and results from 20 SRs underwent meta-analysis. The pooled significant estimate of fatigue reduction was as follows: SMD, −0.50; 95% CI, −0.67 to −0.32; P < 0.001. The subgroup analysis based on the type of CIM intervention revealed that the approach showing higher effects in reducing fatigue thus far is acupuncture: SMD, –0.99; 95% CI = –1.37 to –0.62, P < 0.001; I2 = 84%. CIM therapies showed a significant reduction of fatigue in patients with breast cancer: SMD, –0.46; 95% CI, –0.69 to –0.23; P < 0.001; I2 = 82%. Implications – CIM interventions showed effectiveness in reducing CRF. Subgroup analysis suggested some potential influencing, such as tumor type and specific CIM therapy factors, that require in-depth assessment in future research. Study protocol registration: PROSPERO CRD42020194254.