Purpose of Review: This is a comprehensive narrative review aimed at identifying relevant risk factors associated with peri-implantitis. Recent Findings: Recent studies suggest that water pipes and electronic cigarettes present potentially significant risk factors for peri-implantitis. In addition, we have recently appreciated that the release of titanium particles into the peri-implant tissues is associated with inflammation and disease progression. Yet the question remains as to whether these factors could be sole or major causes of peri-implantitis, or merely additional factors contributing to the aggravation of the disease. Furthermore, the use of zirconia implants does not prevent the development of peri-implantitis, but it has been associated with lower inflammation and marginal bone resorption. Summary: Established peri-implantitis risk factors include periodontal disease, lack of maintenance, cigarette and smokeless tobacco use, hyperglycaemia and obesity. Local risk factors include inadequate plaque control, mucositis, implant's malposition and poorly designed prostheses or presence of excess cement. Potential risk factors requiring additional research include genetic and systemic conditions, high doses of bisphosphonates and hormonal replacement therapy. Occlusal overload, lack of keratinised tissue and local presence of titanium particles seem to aggravate peri-implant disease, but studies are still required prior to drawing definitive conclusions.