Purpose: This meta-analysis investigated the influence of different acid etching times on the retention rate of pit-and-fissure sealants based on clinical trials with a minimum duration of two years. Materials and Methods: A literature search was carried out in electronic databases along with hand searching to identify clinical trials that evaluated pit-and-fissure sealants in permanent molars. From 1280 identified abstracts, 195 studies were selected for full-text analysis, and 28 studies with 36 test groups were included in this meta-analysis. Test groups with etching times of 15 (n = 3), 20 (n = 2), 30 (n = 10), 40 (n = 1) and 60 s (n = 20) were found. Incidence rates of pit-and-fissure sealant losses were modelled using negative binomial regression. Results: The regression analysis did not reveal a significant influence of etching time on the survival of pit-and-fissure sealants based on the identified and included clinical trials. Conclusions: Due to the limited number of clinical data for 15 and 20 s, conclusions regarding very short acid etching times were not possible. On the basis of regression analysis, a minimum of 30-s acid etching might be sufficient prior to fissure sealing. Keywords: acid etching, caries prevention, clinical studies, enamel pretreatment, meta-analysis, pit-and-fissure sealants, systematic review