The optical and electronic properties in an InGaP/InGaAIP multiple quantum well (MQW) grown by using molecular-beam epitaxy utilizing the digital alloy technique were investigated through temperature-dependent photoluminescence (PL) measurements and numerical calculations. The high-resolution transmission electron microscopy images showed that the sample clearly displayed the InGaP wells and the InGaAIP barriers and separate confinement heterostructure layers. The PL measurements at various temperatures were performed to investigate the interband transitions of the InGaP/InGaAIP MQW. The electronic subband energies and the wavefunctions in the InGaP/InGaAIP MQW at several temperatures were determined by using a finite element method employing the standard 8-band k x p Lagrangian. The numerical results for optical interband transition energies from the ground state electron subband to the ground state heavy-hole subband of the InGaP/InGaAIP MQW at various temperatures were in reasonable agreement with the excitonic transition energies observed in the PL measurements.