We calculate the effect of a homogeneous electric field on electrons, holes and excitons confined in a quantum well structure consisting of alternate thin layers of well and barrier material. The electric field which acts perpendicular to the quantum well is taken as a perturbation on the quantum well structure confining the charges. The electron and hole energies in the conduction and valence subbands are calculated by solving a one-dimensional Schrödinger equation. The exciton binding energy is calculated using an improved excitonic model. Results obtained indicate the importance of higher-order excitons in optical transitions at high electric fields.