Plantar fasciitis is associated with alteration of vertical ground reaction forces and pain that needs to be treated by using foot orthosis. The purpose of the study is to determine Impact of Functional Foot Orthosis on Vertical Ground Reaction Force and Pain in Persons with Plantar Fasciitis.There was significant improvement in pain as well as ground reaction force by using functional foot orthosis. Vertical ground reaction forces were significantly different at loading response and at terminal stance after use of the orthosis than before but no significant change was seen at midstance. Pain ratings mean in symptomatic foot measured by the Visual analog scale were significantly less than before use of the orthosis. It may be concluded that Functional foot orthosis significantly reduces pain experienced during walking and normalizes the vertical ground reaction force in subjects with plantar fasciitis.