Overhang refers to the extension of restoration material from the cavity. It has an important role in decay, plaque accumulation and periodontal disease, so the aim of this study is determining the frequency of restoration overhang in patients in Anzali, Guilan. Materials and methods: This descriptive cross-sectional study was completed using 293 patients who visited for routine checkups. The overhangs were examined on the basis of the cavity type, restoration type, tooth location, and age by direct observation using an explorer, dental floss. After the initial diagnosis of the overhang, the radiographic reports were examined for final confirmation. Results: 41.2%, 0%, 18.2%, and 38.1% were observed in cavity classes II, III, IV, and V, respectively. 35.8%, 38.2%, 28.1%, and 25% were observed in mesial, distal, buccal, and lingual regions, respectively. The highest rate of overhang frequency in the first molar teeth was 50% and the lowest overhang amount occurred in the lateral and canine teeth at 25% and 27.3%, respectively. Most amalgam restorations had overhang (37.7%) and the highest amount of overhang was in the upper jaw (42.5%). The highest amount of overhang frequency was observed on the left (41.6%). There was no significant difference in overhang frequency between men and women. The lowest and highest amounts of overhang were observed in the age groups of <30 (26.9%) and 30-39 (47.8%), respectively, and was found to be statistically significant. Conclusion: The overall frequency of restoration overhang was 36.6%, most of which was in class II amalgam restoration in the left first molar teeth in 30-39 year-olds.