Background: The goal of this systematic review and meta-analysis is to determine the effect of diet on telomere length. Methods: We searched the following databases: MEDLINE, Embase, LILACS, CINAHL, ISI Web of Science, and Scopus, as well as the Cochrane Central Register of Controlled Trials and the National Institutes of Health, from inception to December 2016. Articles that assessed effects of diet on telomere length were included. Results: A total of 2,128 studies were identified, 30 were read in full, and 7 were systematically reviewed. Five RCTs were included in the meta-analysis, covering 9 diets; a total of 533 participants were included. Study heterogeneity (I2) was 89%, and differences were not identified regarding average telomere lengths (mean difference 1.06; 95% CI –1.53 to 3.65). Conclusion: The available evidence suggests that there is no effect of diet on telomere length, but the strong heterogeneity in the type and duration of dietary interventions does not allow any final statement on the absence of an effect of diet on telomere length.