Breast cancer is a heterogeneous disease driven by complex interactions between genetic, hormonal, metabolic, lifestyle, and environmental factors. Among environmental exposures, agricultural pesticides represent potential contributors to breast carcinogenesis through endocrine-disrupting, oxidative, genotoxic, and epigenetic mechanisms. Utilizing a structured search strategy across PubMed, Scopus, and Web of Science, this review provides a critical synthesis of current evidence linking major pesticide classes with breast cancer dynamics, strictly distinguishing preclinical mechanistic findings from human epidemiological data. Special attention is given to endocrine-disrupting pathways involving estrogen receptors and aromatase hyper-induction, alongside oxidative stress, matrix metalloproteinase activation, epithelial–mesenchymal transition, cancer stemness expansion, and therapeutic resistance. We further evaluate the cytoprotective potential and severe bioavailability bottlenecks of dietary phytochemicals in mitigating pesticide-induced damage. Finally, we address critical methodological limitations, such as exposure misclassification, confounding factors, and the gap between micromolar in vitro doses and realistic nanomolar human exposures, stressing that preclinical mechanisms cannot prove direct clinical causality Therefore, integrating prospective multi-omics biomonitoring with cumulative cocktail risk assessments is essential for evidence-based primary prevention.