BACKGROUND: Peroneus tertius muscle (PTM) is a muscle of the anterior compartment of the leg. It is a highly variable muscle with a prevalence rate ranging from 42%-100% in different populations worldwide. We sought to explore the frequency of PTM and its existing variants, based on surface anatomical evaluation of the foot, in Omani subjects.METHODS: In this study, a total of 222 adult Omani subjects (total 444 feet) were examined for the presence of PTM. The presence of PTM and its morphological types were identified based on surface anatomical examination using a standard palpation method. Descriptive statistics were used to present the data. The gender influence on the occurrence of PTM was determined by the Chi-square test.RESULTS: The frequency of PTM was observed in 59.9% of total feet. A statistically significant gender difference with male dominance was observed on both right (p = 0.02) and left (p <0.01) feet. Regarding PTM types, the F2 type was most common on both right (38.5%) and left feet (46.2%). The bilateral occurrence of PTM was found in 47.7% of cases.CONCLUSION: The frequency of PTM in Omani subjects is considerably high when compared to other Arab populations. The baseline information on the PTM proportion and distribution of its types is clinically important for physiotherapists and orthopedic surgeons.