IMPORTANCE: Reliable estimates of the prevalence and risk of suicide and suicidal ideation (SI) among childhood cancer survivors (CCSs) are crucial in informing efforts to address this issue. OBJECTIVE: To systematically evaluate the prevalence and risk of suicide and SI among CCSs. DATA SOURCES: A literature search was conducted of PubMed, Embase, Cochrane Library, and PsycINFO from January 1, 2000, to November 17, 2024. STUDY SELECTION: All noncontrolled and controlled studies that evaluated the prevalence and risk of suicide and SI and drew comparisons between CCSs and their counterparts. Studies including participants older than 25 years, no reported outcomes, case studies, case reviews, and review articles were excluded. DATA EXTRACTION AND SYNTHESIS: The Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline was followed with prospective PROSPERO registration. Prevalence was pooled for single-arm studies. Relative risk ratio (RR) was pooled for double-arm studies. Metaprop was used to meta-analyze the prevalence of suicide and SI under a generalized linear mixed model. For dichotomous outcomes, meta-analyses were performed to compute the RR of the psychological outcome compared with controls. MAIN OUTCOMES AND MEASURES: Prevalence of suicide and SI, the RR of suicide and SI among CCSs compared with controls, and risk factors associated with suicidality outcomes. RESULTS: From 531 records, 16 studies were included. Studies on suicide included 148 869 participants and studies on SI included 20 140 participants. The prevalence of suicide among CCSs was 0.30% (0.13%-0.69%) and of SI was 9% (95% CI, 7%-11%). There was a significantly increased risk of SI among CCSs compared with controls (RR, 1.67 [95% Cl, 1.39-2.01]), but not of suicide (RR, 1.50 [95% CI, 0.63-3.62]). Subgroup analyses suggested that prevalence of SI is much higher during the active cancer period than years after (proportion, 0.14 [95% CI, 0.10-0.19] vs 0.08 [95% CI, 0.06-0.09]). The systematic review identified preexisting mental illness, poor physical health, older age, male sex, and being single as risk factors associated with suicidality outcomes. CONCLUSIONS AND RELEVANCE: In this meta-analysis of suicide and SI among CCSs, the risk of suicide was no different among CCSs compared with controls, but CCSs had a higher risk of SI. Future studies are needed to explore suicidality outcomes among CCSs to guide targeted support policies.