Introduction: Lichen sclerosis (LS) is a chronic inflammatory skin disease, mostly affecting the anogenital region. Patients with LS have a higher risk of developing anogenital squamous cell carcinoma (SCC), although exact numbers are not known. Objective: To systematically review the absolute risk (AR) and incidence rate (IR) of developing SCC in patients with anogenital LS, as well as patient characteristics that influence the risk of developing LS associated SCC. Methods: A search was performed through the databases of Pubmed and Embase. Five reviewers independently screened the articles on title/abstract and full text published before 31st of July 2019. The selected articles were critically appraised using the Quality In Prognostic Studies tool. Results: Of 2238 titles and abstracts assessed, 15 studies were selected to be analysed. The AR of developing SCC in patients with LS varied between 0.21 and 3.88% for women and 0.00–0.91% for men across the included studies. The IR was 0.65–8.89/1000 person-years for women and 0.00–6.49/1000 person-years for men. This risk for women seemed to be increased by age, the presence of vulval intra-epithelial neoplasia (VIN), a long history of LS, late diagnosis of LS and partial compliance of treatment with topical corticosteroids. For men, no determinants were found. Conclusion: We found fair evidence that the AR of developing SCC in patients with anogenital LS varied between 0.21 and 3.88% for women and 0.00–0.91% for men. Therefore, we recommend regular follow up and compliant treatment with topical corticosteroids, especially in older women.