Abstract: The deformity of flat foot (Pes planus) is a serious health problem causing gait and postural defects in all age groups. The use of anthropometric measurement has found a very salient role in the analysis of the difference that exist in the anthropometric measurement taken from individuals with flat and those with normal foot. The aim of this research work was to determine the incidence of flat foot amongst school aged children and to also determine foot anthropometry (comparison between flat and normal foot) with respect to age and gender amongst Yoruba ethnic group in Nigeria. A total of 200 students comprising of 100 males and 100 females of Yoruba origin aged 9-14 years were investigated. The following parameters were measured: Navicular Height (NH), Medial Malleolar Height (MMH), Lateral Malleolar Height (LMH), Foot Length (FL) and Transverse Arch Length (TAL) with the aid of a ruler, marker pen and measuring tape. Mean and standard deviation of the measured parameters and other variables were determined by descriptive statistic report and t-test while their level of significance were determined using ANOVA Post Hoc Tests and independent sample t-test at (p<0.05). A total of 25 individuals had flat foot comprising of 13 males and 12 females. The overall incidence of flat foot was 25% with incidence of 13% among lies and 12% among females. Following independent sample t-test analysis of the data, significant differences were found for all the measured parameters except Foot Length (FL) when children with normal foot were compared with those with flat foot. This study showed flat foot has high incidence among school aged children in Yoruba lie group with males having higher percentage incidence than females. It also showed that incidence of flat foot decreased with age all the measured anthropometric foot parameters showed male preponderance over females for normal foot type and also for flat foot except the Medial Malleolar Height (MMH) which was higher in than males. In conclusion flat footedness is one of the most prevalent foot abnormalities among the Yoruba ethnic group of Nigeria which decreases with age and has male preponderance.