This meta-analysis evaluated the efficacy of Self-Help Cognitive Behavioral Therapy for Insomnia (SH-CBTI), explored potential moderators of treatment outcome and evaluated the quality of evidence. Thirty five studies were included, and results showed: (a) The immediate efficacies of SH-CBTI for SE, SOL, WASO, TST, SQ, depression and anxiety were 0.66, −0.52, −0.47, 0.20, 0.34, −0.32 and −0.33 respectively; (b) SH-CBTI and face-to-face CBTI showed an equal efficacy at post-treatment while both minimal treatment and pharmacotherapy showed significantly smaller effects; (c) Comorbidities and support formats had a significant impact on the outcome. Evaluation on the quality of evidence showed that qualities of SE, WASO, TST, depression and anxiety are moderate, which means that the true effect is likely to be close to the estimated one. Low-level evidence supports SOL and SQ qualities, which indicates that the true effect may be substantially different from the estimated one.