Flexible flatfoot is one of the most common musculoskeletal deformities in children and may affect lower-limb function, gait pattern, and quality of life if it persists. Accurate assessment of this condition is essential for effective screening and appropriate clinical decision-making. The present study aims to investigate the correlation between the Foot Posture Index (FPI-6) and pedographic parameters, including Clarke's angle, the Chippaux–Smirak Index, and the Staheli Index, in children with flexible flatfoot. This descriptive-correlational study will assess foot posture using the FPI-6 and analyze plantar footprints through pedographic measurements. The relationship between the outcomes of these assessment methods will be examined using appropriate statistical analyses. It is anticipated that a significant correlation will be found between the FPI-6 and the pedographic indices, supporting the use of FPI-6 as a simple, rapid, inexpensive, and radiation-free clinical tool for the screening and evaluation of flexible flatfoot in children. The findings of this study may contribute to improving clinical assessment strategies and reducing reliance on radiographic imaging and other costly diagnostic techniques.