Objective: Clinical Practice Guidelines (CPGs) have an indispensable role in guiding the selection of various treatments for insomnia, however, little is known about the quality of released insomnia CPGs. This study aims to critically appraise the quality of existing insomnia CPGs and identify quality limitations. Methods: PubMed, Web of Science, Embase, China National Knowledge Infrastructure, Wanfang, China Biology Medicine disc, and 6 databases of international guideline developing institutions were systematically searched. CPGs on the diagnosis or treatment of insomnia were included. Reviewers independently extracted basic information and development methods, and assessed methodological quality and reporting quality using the Appraisal of Guidelines for Research and Evaluation (AGREE) II tool and Reporting Items for practice Guidelines in Healthcare (RIGHT) checklist respectively. Intraclass correlation coefficients (ICCs) were used to measure the agreement among reviewers and assess inter-rater reliability. Results: Twenty-six CPGs were identified that focused on adults, children, or children with autistic spectrum disorder, patients in the intensive care unit, patients with cancer and pregnant, lactating or menopausal women. Twenty-two CPGs used nine grading systems to rate the level of evidence and strength of recommendation. 53.85% CPGs were classified as "recommended with modification" according to the AGREE II scores (ICC from 0.64 to 0.90), and 2 CPGs were "recommended". The "clarity of presentation" domain achieved the highest mean score (67.9% +/- 11.04%) but the "applicability" domain (37.1% +/- 12.67%) achieved the lowest. The average reporting rate of RIGHT items in all guidelines was 67.87%. Conclusions: The quality of guidelines varied substantially. Guideline developers should realize the importance of guideline applicability, patients' preferences and values. (c) 2022 Elsevier B.V. All rights reserved.