In the present work, we investigated the influence of step bunching on the optical properties of InGaAs/GaAs quantum wells (QWs) grown by molecular beam epitaxy (MBE) on vicinal surfaces. Photoluminescence (PL) measurements showed a larger full width at half maximum (FWHM) of the emission coming from the QWs grown on the vicinal surfaces with respect to the nominal sample. Transmission-electron-microscopy (TEM) measurements revealed the presence of step bunches that clearly roughen the interfaces of the heterostructures and worsen the optical properties of the samples.