Optical fiber sensors with light weight, small size and immunity to electromagnetic interference have been found to be a promising device for use in the development of smart structures. It is well known that the strain transfer from the host structure to the optical fiber sensor is dependent on the bonding characteristics such as adhesive layer and bonded length. In this investigation, the optical fiber sensor is surface bonded on the host structure. A theoretical model consisting of the optical fiber, adhesive layer and host material, is proposed to determine the strain in the optical fiber sensor induced by the host structure. The theoretical predictions were validated with the numerical analysis using the finite element method.