The room-temperature vapor phase overtone spectra of o-, m-, and p-xylene have been recorded in the CH stretching region corresponding to Deltanu(CH) = 2-6 with conventional near-infrared spectroscopy (Deltanu(CH) = 2 and 3), intracavity titanium: sapphire (Deltanu(CH) = 4 and 5) and dye laser photoacoustic spectroscopy (Deltanu(CH) = 6). Absolute oscillator strengths have been measured from the conventional spectra and relative oscillator strengths within a given overtone from the conventional and photoacoustic spectra. The aryl region of the spectra can be interpreted simply in terms of a number of nonequivalent and independent local modes. The methyl region of the spectra is more complex. The methyl band profiles in the overtone spectra of m-xylene and p-xylene are very similar to each other and to that of toluene and differ significantly from the methyl band profiles in the spectra of o-xylene. We use a simple anharmonic oscillator local mode model with ab initio calculated dipole moment functions to calculate oscillator strengths of the aryl transitions. The methyl band profiles are simulated on the basis of a model that incorporates the harmonically coupled anharmonic oscillator local mode model for the CH stretching modes and a rigid rotor basis for the methyl internal rotation (torsion). The model parameters are calculated ab initio. The dipole moment function is expressed in a series expansion in both the CH displacement coordinate and the torsional angle whereas the frequency, anharmonicity, and torsional potential are expressed in Fourier series of the torsional angle. The difference in the methyl band profiles in o-xylene, and in m- and p-xylene are ascribed mainly to differences in the torsional potential and the dipole moment function. Our simulations have successfully reproduced the methyl band profiles in the xylene spectra and the relative aryl to methyl intensities.