The effect of impurity concentration on the line spectra of holes bound to B, Al, and Ga acceptors in silicon has been studied at 21°K. Details of the spectra (i.e., relative positions, line shapes, intensities) differ for the different acceptors. Below an acceptor concentration of about 1016/cm3 the spectra are concentration-independent under the conditions of measurement. Above 1016/cm3 the spectral lines begin to broaden and by ~1018/cm3 the line structure has been almost completely destroyed. A qualititive discussion of the concentration effects is given.