Periodontitis is one of the most common oral diseases and is characterised by a chronic inflammatory disorder caused by the complex interaction between microbial plaque and the host immune system. It significantly affects both physical and mental health as well as quality of life. Over the past 30 years, the burden of periodontitis in China has been rising, and it is expected that the incidence of periodontal disease will continue to increase over the next 25 years. Various factors, such as smoking, diabetes, immune levels, genetic predisposition, stress, and age, can influence the incidence of periodontitis and increase the risk of periodontitis. Circadian rhythms are closely related to the homeostasis of periodontal tissues, regulating their sensitivity to external injuries and their ability to repair. Under normal circadian rhythms, periodontal tissues can effectively resist external damage and promote the repair of damaged cells. However, when circadian rhythm disorders occur, the self-protection and repair mechanisms of periodontal tissues are impaired, leading the accumulation of continuous damage. The impact of circadian rhythm disorders on periodontal tissues is multifactorial, influencing the self-protection and repair mechanisms through regulation of inflammatory response, oxidative stress, and DNA damage repair, thereby promoting the onset and progression of periodontitis. Currently, the exact mechanisms by which circadian rhythm disorders exacerbate periodontitis remain unclear. This article reviews the effects of circadian rhythm disorders on periodontitis and possible mechanisms, providing evidence to further clarify their relationship.