Background: To our knowledge, no previous systematic review and meta-analysis of doping prevalence in sport from indirect estimation models (IEM) exists. Objective: To conduct a systematic review and meta-analysis of empirical IEM-based studies of admitted doping prevalence in sport. Methods: We conducted electronic database and ad hoc searches up to March 2025, and estimated lifetime and past year prevalence rates through a cross-classified model including prevalence (lifetime vs. past year), sample (competitive vs. recreational) and sports (multi-sport vs. single-sport) types. Results: Forty-six records (K) were included in the review (k [subset records included in the meta-analysis] = 30, n [independent studies from the records] = 34). The World Anti-Doping Agency’s definition of doping use was applied for data collection in most studies (k = 18), and doping prevalence was mostly assessed as past year/season (k = 20). Studies included in the meta-analysis were mostly conducted in Europe (k = 22) and applied the Unrelated Question (k = 8) and Forced Response with Cheater Detection (k = 6) models. Study participants were mostly multi-sport (k = 20) and competed at diverse levels, and most data (k = 28) was collected outside sport events. The corpus included articles that re-analysed existing data (k = 4). Lifetime prevalence was highest for multi-sport competitive athletes (22.6%) and lowest for single-sport competitive athletes (12.7%), whereas past year prevalence was highest for single-sport recreational sportspersons (15.5%) and lowest for multi-sport recreational sportspersons (8.7%). Conclusions: Under IEM, about one of five multi-sport competitive athletes admitted to ever doping whereas about one of six of single-sport recreational sportspersons admitted to doping in the past year. Furthermore, multi-sport (vs. single-sport) competitive athletes show relatively higher doping prevalences, whereas single-sport (vs. multi-sport) recreational sportspersons report relatively higher doping prevalences. Secondary (re-)analysis presents a novel methodological challenge for meta-analyses. Registration PROSPERO: CRD42022373691.