Introduction: Honey and honey-based preparations have attracted interest as potential sources of anticancer compounds, but evidence in prostate cancer remains heterogeneous. This systematic review aimed to synthesize and critically appraise in vitro evidence of honey-based preparations against human prostate cancer cells. Methods: PubMed, Scopus, and ScienceDirect were searched on 19 August 2026 without publication-year restrictions. Primary in vitro studies evaluating whole honey, crude honey extracts, or honey-based preparations in human prostate cancer cell lines were included. Methodological reliability was assessed using the 18-criterion Toxicological data Reliability Assessment Tool (ToxRTool). Results: Seven studies were included, primarily involving PC-3 and, in some studies, DU145 cells. Outcomes included cell viability, cytotoxicity, proliferation, cell-cycle progression, migration, invasion, adhesion, and molecular or inflammatory endpoints. Honey-based preparations showed inhibitory effects, although findings varied by honey type, preparation, concentration, exposure duration, cell line, and assay methodology. Six studies were classified as ToxRTool Category III and one as Category I. Conclusion: Honey-based preparations may have anticancer potential against human prostate cancer cells in vitro, but evidence remains limited by substantial heterogeneity, methodological limitations, and potential assay interference. Further standardized and well-controlled studies are needed before in vivo and clinical investigation.