Breast cancer is the most prevalent malignancy among women. Certain air pollutants have carcinogenic and estrogenic properties that can contribute to breast cancer development. This systematic review aimed to investigate the association between air pollution and breast cancer based on epidemiological evidence. This systematic review included articles published between 2013 and 2022 from Scopus and PubMed databases, focusing on cohort and nested case-control studies examining the association between outdoor air pollution and breast cancer. A total of 25 articles were included. A total of eight outdoor pollutants were analyzed, with seven showing a significant association with breast cancer risk. Specifically, the strong association between benzo[a]pyrene and breast cancer risk was reported. Furthermore, all four studies on nitrogen oxides (NO_x), fifteen out of eighteen (83.33%) on particulate matter less than 2.5 µm (PM_2.5), nine out of thirteen studies (69.23%) on nitrogen dioxide (NO₂), and three out of seven studies (42.86%) on particulate matter less than 10 µm PM₁₀ showed an association with breast cancer risk (hazard ratio [HR]: 1.05–1.56; odds ratio [OR]: 1.03–1.86). In contrast, only one out of three studies (33.33%) on O₃ (HR: 0.76–1.03) and all studies on cadmium (OR: 0.88–0.97) suggested a negative association with breast cancer risk. None of the studies on black carbon found an association with breast cancer risk. It is important to note the methodological limitations of this review, including potential publication bias due to the inclusion of only English-language articles and a regional focus on developed countries, which may limit the generalizability of findings. This study suggests that exposure to outdoor air pollutants is linked to an increased risk of breast cancer. Further research is needed to establish a causal relationship and the mechanisms by which environmental pollutants may trigger carcinogenic effects and contribute to breast cancer development through epigenetic pathways.