This systematic review aimed to synthesize experimental evidence on the anticancer effects of Lacticaseibacillus rhamnosus (L. rhamnosus) and its derivatives against colorectal cancer (CRC) cell models. Eligible studies investigated probiotics, postbiotics, or bioactive compounds derived from L. rhamnosus with an in vitro component; studies relying solely on in vivo animal models, clinical trials, or observational designs were excluded. PubMed and Scopus were searched to identify relevant studies. Risk of bias was assessed using a modified QUIN tool, and extracted data were tabulated. Owing to incomplete numerical data, meta-analysis was not feasible, and the results were synthesized accordingly. Seventeen studies were included. L. rhamnosus and its derivatives reduced CRC cell proliferation, induced apoptosis, and caused cell cycle arrest. Reported mechanisms included upregulation of Bax, caspase-3/9, and p53; downregulation of Bcl-2/Bcl-xl; inhibition of Wnt/β-catenin signaling; reduced invasion and migration; increased reactive oxygen species; and immunomodulatory effects. Key limitations were heterogeneity in interventions, dosages, exposure periods, and cell lines, along with incomplete reporting, which precluded quantitative synthesis. Overall, preclinical evidence indicates multimodal anticancer effects of L. rhamnosus in CRC models; however, standardized reporting and translational research are required.