Periodontal disease (PD) and benign prostatic hyperplasia (BPH) are two highly prevalent conditions of great international health and economic importance. PD, the chronic inflammatory gum bacterial disease, has been implicated in systemic inflammation and spread of bacteria that can cause the pathogenesis of BPH. BPH, the non-malignant enlargement of the prostate, arises in aging men and is driven by multifactorial determinants including chronic inflammation and hormnes. There is emerging evidence of the two-way link between PD and BPH, with both conditions sharing risk determinants such as age, tobacco, obesity, and systemic inflammation. This scoping review synthesizes the current state of the literature on the relationship between PD and BPH. Observational studies demonstrate a strong association with increased risk and severity of BPH in PD patients, including after the adjustment of confounders. Insight into mechanisms, e.g., the “oral-prostate axis,” suggests that periodontal bacteria may translocate to the prostate tissue where they elicit local inflammation and remodeling of the tissue. Significant gaps remain, including the provision of long-term studies to establish causality and intervention studies to investigate the influence of periodontal therapy on the development of BPH.