Abstract Purpose: This systematic review with meta-analysis aimed to elucidate the physiological adaptations of high-intensity interval training (HIIT) compared to moderate-intensity continuous training (MICT) or usual care (UC) on physical fitness, health parameters and patient-reported outcomes in cancer survivors. Methods: The electronic databases PubMed, Web of Science and EMBASE were searched according to PRISMA guidelines until October 4th, 2018. Adult patients of various cancer entities, performing HIIT compared to MICT or UC were eligible for inclusion. The primary outcome of interest was cardiorespiratory fitness (VO2peak). Secondary outcomes included body composition measures, blood-borne biomarkers as well as the patient-reported outcomes quality of life and cancer-related fatigue. Mean differences (MD) were calculated and pooled to generate effect sizes for VO2peak. Results: A total of 1453 studies were identified with finally 12 articles included. Mean intervention duration was 6.7 ± 3.0 weeks, with 2.8 ± 0.5 trainings per week. Pooled analysis for VO2peak revealed greater effects of HIIT compared to UC (MD 3.73; 95% CI: 2.07, 5.39; p < 0.001) but not MICT (MD 1.36; 95% CI: −1.62, 4.35; p = 0.370). Furthermore, HIIT showed to be more beneficial in reducing fat mass compared to MICT, but no superior effects were found of HIIT compared to MICT for changes in quality of life, cancer-related fatigue or lean mass. Conclusion: HIIT appears to be more beneficial than UC in cancer survivors for most of the outcomes of interest. However, HIIT may not be superior to MICT in terms of improving physical fitness or patient-reported outcomes.