Betel quid (BQ) chewing, a deeply ingrained cultural practice in South Asia and beyond, has significant implications for oral health, particularly periodontal and peri-implant conditions. This chapter comprehensively reviews the effects of habitual BQ chewing on periodontal health, highlighting its role in exacerbating gingival inflammation, increasing plaque accumulation, and accelerating alveolar bone loss. Studies indicate that BQ chewers exhibit higher periodontal disease parameters, including increased bleeding on probing, probing depth, and marginal bone loss, compared to non-chewers. The presence of tobacco and areca nut in BQ further aggravates periodontal inflammation by promoting oxidative stress and altering the oral microbiome, leading to microbial dysbiosis with an increased prevalence of periodontopathogenic bacteria. Limited research exists on the impact of BQ chewing on peri-implant health, but preliminary findings suggest that it may contribute to peri-implant mucositis and peri-implantitis by impairing soft tissue healing and inducing crestal bone loss. Given the public health concerns associated with BQ consumption, awareness campaigns, early screening, and targeted interventions by healthcare providers are crucial. Further longitudinal studies are needed to establish a definitive causal relationship between BQ chewing and peri-implant diseases and to develop effective preventive and therapeutic strategies.