BACKGROUND Smoking is an independent risk factor for periodontal disease and tooth loss. BACKGROUND Smoking impairs inflammatory and immune responses to periodontal pathogens, and exerts both systemic and local effects. Periodontal disease is increased both in prevalence and severity in smokers. Smoking is a predisposing factor to acute necrotizing ulcerative gingivitis and is associated with an increased rate of periodontal disease in terms of pocket formation and attachment loss, as well as alveolar bone loss. Cigar, pipe, water-pipe and cannabis smoking have similar adverse effects on periodontal health as cigarette smoking. Passive smoking is also an independent periodontal disease risk factor. Smokeless tobacco is associated with localized periodontal disease. Smokers respond less favourably to both non-surgical and surgical treatments and have higher failure rates and complications following dental implantation. Smoking cessation may halt the disease progression and improve the outcome of periodontal treatment. CONCLUSIONS Smoking cessation counselling should be an integral part of periodontal therapy and prevention.