Background: Anti-diabetic medications are integral for glycemic control in diabetes. Nonadherence to drugs can alter blood glucose levels, resulting in complications. Adherence to antidiabetic medications reported by patients and the factors associated with medication adherence among adult patients with diabetes mellitus were explored. Methods: This cross-sectional study was carried out among patients with type II diabetes mellitus attending the Internal Medicine Department of a hospital in the United Arab Emirates. Consecutive patients were selected, and data regarding their medication adherence were collected using a questionnaire. Data analysis was carried out using SPSS-20. The chi-square test was performed to examine the associations between categorical variables; a two-sided P Value < 0.05 was considered significant. Results: A total of 132 patients participated in the study (63 males; 69 females). The mean age (standard deviation) of the respondents was 54 years (SD 10.2). The self-reported adherence rate to anti-diabetic drugs was 84%. The most common reason for non-adherence was forgetfulness, and the adherence rate was similar in both genders. Patients with Bachelor’s and Master’s degree reported greater adherence rate to anti-diabetic medication in comparison to the secondary school educated. Conclusion: The self-reported adherence rate to anti-diabetic medications was 84%, and forgetfulness was the most common reason for non-adherence. Future studies on strategies to improve adherence rate should be considered.