Background: Mutations in the TP53 gene can alter its tumor suppressor functions, thereby promoting oncogenic activity. The TP53 IVS3 16 bp genetic variant overlaps with nucleotide sequences that can alter regulatory structures, potentially affecting its function. The aim of the present study was to evaluate the association between TP53 IVS3 16 bp genetic variant and the risk of breast cancer (BC) in women from western Mexico. Methods: The study included 220 women diagnosed with BC and 198 cancer-free controls. Clinical and demographic data were collected through structured questionnaires and verified with medical records. Genotyping of the TP53 IVS3 16 bp genetic variant was performed using polymerase chain reaction (PCR) and visualized on 6% polyacrylamide gels. Results: Compared to controls, women with BC more frequently reported a family history of the disease and menopausal status (p < 0.05). Genotypic analysis revealed that carriers of the D/I genotype and the combined D/I + I/I genotypes were associated with a reduced risk of BC in codominant (OR = 0.53; 95% CI 0.32–0.88) and dominant (OR = 0.57; 95% CI 0.35–0.93) models. Conclusions: The D/I and D/I + I/I genotypes in codominant and dominant models showed a lower risk against BC. More studies are needed to confirm these findings.