Breast cancer incidence and mortality rate in Cameroonian women is incredibly high, thus there is need for more effective therapy. Xylopia aethiopica dry fruits are traditionally used for both nutritional and medicinal purposes, including the management of diverse ailments such as cancer. This study evaluated the in vitro and in vivo anti-mammary cancer potential of X. aethiopica. The cytotoxic activity of the ethanolic extract of X. aethiopica dry fruits was assessed at different concentrations against MDA-MB 231 and MCF-7 cells using the MTT assay. Additionally, clone formation, apoptosis/necrosis, cell adhesion, cell migration, and chemotaxis were examined. Furthermore, the chemo-preventive potential of X. aethiopica dry fruit extract (XAE) was evaluated on breast tumors induced by DMBA in 42 female rats of age 45-55 days (~80 g). The normal (NOR) and negative (DMBA) control groups were daily treated with the vehicle, while the positive (Tamox) and test (XAE) groups were administered tamoxifen (3.3 mg/kg) and X. aethiopica extract (75, 150, and 300 mg/kg BW), respectively for 20 weeks. Parameters such as tumor volume and burden, tumor incidence, CA 15-3 serum level, inflammatory status, antioxidant and histopathology were evaluated. X. aethiopica significantly (p < 0.05) decreased ER+ (MCF-7) and ER- (MDA-MB 231) breast adenocarcinoma cell growth from 12.5 to 100 μg/mL after 72 h. At the 100 μg/mL concentration, clone formation, cell proliferation, and migration were notably decreased in MDA-MB 231 cells after 48 h, while there was an observed rise in cell adhesion to the collagen extracellular matrix. Additionally, there was a rise in apoptotic cell count (p < 0.01) and caspase-3 activity (p < 0.05) observed in MDA-MB 231 cells following exposure to XAE at 100 μg/mL. XAE, across all tested doses, demonstrated significant reductions in tumor incidence, burden, and volume, akin to tamoxifen, compared to untreated rats (DMBA). Furthermore, there was an elevation in antioxidants (SOD, CAT, and GSH) and a decrease in pro-inflammatory cytokines (INF-γ, TNF-α, IL-12, and IL-6) observed at all tested doses. Overall, X. aethiopica dry fruit displays anticancer potential through caspase-3-dependent apoptosis pathways, alongside antioxidant and anti-inflammatory activities.