The present systematic review and meta-analysis were conducted to find the degree by which the Iranian diabetic patients were informed about their disease in term of health literacy. The search was carried out in databases including the PubMed, MEDLINE (PubMed), Scopus, Embase, Cochrane Library, ProQuest, Web of Science, Science Direct and Wiley and also domestic databases including the Iranian Academic Center for Education Culture and Research (sid. ir), the Iranian Research Institute for Information Science and Technology (IranDoc. ac. ir), Barakat Knowledge Network System (barakatkns. com), the national publications database (magiran. com) and also Google Scholar and Elmnet search engines. All the original studies published by Oct 20, 2018, in Persian or English, to assess the health literacy of adults with diabetes were included in the study. Ultimately, 17 articles were included in the meta-analysis. The meta-analysis was carried out using the fixed-effects method using Stata-11.2. The pooled mean score of health literacy was 56.65 out of score of 100, and its 95% CI was estimated as 49.85 to 63.45. No significant heterogeneity could be reported for the articles included in the meta-analysis (I-squared= 21.3%, P= 0.177). The pooled mean scores with the CI of 95% by gender based on the study population in women and men were estimated as 47.97 and 50.06 respectively. Health literacy is not high in Iranian diabetic patients and is rather inadequate in most of them in both genders. Diabetic women have somewhat lower health literacy compared to diabetic men.