The authors have grown a series of (Ga,Mn)As/AlAs multiple quantum well structures with smooth and abrupt interfaces by molecular beam epitaxy to study the confinement effect on the spin polarization of bound holes in (Ga,Mn)As quantum wells (QWs). With respect to the growth conditions, a compromise between the requirement of low-temperature growth and high AS(4)/Ga flux ratio for the (Ga,Mn)As QWs to avoid Mn segregation and MnAs cluster formation on the one hand and the requirement of high-temperature growth and low AS4/Ga flux ratio for two-dimensional growth of the AlAs barriers on the other hand was chosen, using a substrate temperature of 250 degrees C. Detailed studies of the hot-electron photoluminescence polarization in a magnetic field revealed that the confinement effect strongly modifies the electronic state of single Mn acceptors and the acceptor impurity band. However, even in narrow QWs the polarization of bound holes is more sensitive to random stress and/or electric fields in the QW plane than to confinement. Internal random stress and/or electric fields suppress the circular and linear polarizations, and the expected enhancement of the polarization of bound holes due to confinement is therefore experimentally not observed. (C) 2007 American Vacuum Society.