Purpose <p>To summarize the impact of exercise interventions on cardiorespiratory fitness (CRF) in childhood cancer survivors (CCS) and determine optimal FITT (Frequency, Intensity, Type, Time) parameters to improve CRF in CCS.</p> Methods <p>Electronic databases Medline, Embase, Web of Science, Scopus, Central, CINAHL, SPORTDiscus and clinicaltrials.gov were systematically searched from inception to 09/04/2025. Reference lists of relevant articles and review papers were manually screened. Studies included CCS &lt; 19 years at diagnosis, undergoing any type of exercise intervention with peak oxygen consumption (VO₂peak) and/or 6-min walk test (6MWT) distance as outcomes for CRF.</p> Results <p>Ten studies involving 309 participants (55.7% male, 6–23 years) were included. Exercise interventions significantly improved VO₂peak (<i>n</i> = 6 studies; MD = 4.40 ml/kg/min; <i>p</i> &lt; 0.01; 95% CI, [1.86; 6.94]) and 6MWT (<i>n</i> = 5 studies; MD = 53.59 m; <i>p</i> = 0.01; 95% CI, [16.31; 90.88]) compared to usual care in CCS. Meta-regression revealed no significant associations between frequency, intensity, type, time, and VO₂peak (<i>n</i> = 6) or 6MWT (<i>n</i> = 3).</p> Conclusion <p>Exercise interventions significantly improved CRF in CCS. Due to the limited amount and heterogeneity of included studies, optimal FITT parameters to increase CRF in CCS could not be identified. More randomized controlled trials with large sample sizes are needed to complement existing evidence and increase the robustness of the findings.</p>