We have measured the room temperature photoreflectance spectrum from molecular beam epitaxy InAlGaAs epilayers of different compositions, and a InGaAs(7.0 nm)/InAlAs(8.8 nm) multiple quantum well (MQW). The spectra have been fitted by a complex resonance line shape expression. A linear energy gap vs. composition relationship has been obtained for the epilayers. In addition to all the allowed transitions of the MQW, we have observed features from a symmetry-forbidden transition: there is good agreement between the experimentally determined energies of the various features and a theoretical calculation.