In this paper, the application of photoacoustic methods to study thermo-optical and spectroscopic properties of polymers is described. The Photoacoustic Spectroscopy, the Two-Beam Phase-Lag and also the so-called Open Photoacoustic Cell methods will be presented. The theoretical basis for quantitative measurements is discussed together with the advantages and limitations of the methods as compared with conventional measurements. Applications for spectroscopic and depth profile analysis and also for thermal properties measurements in several polymers samples are discussed.