The photoacoustic signal from a finite cylindrical solid sample under excitation by an arbitrary incident source is derived and is in general a complicated function of the beam profile, optical, thermal, and geometrical properties of the gas, sample, and backing material in the cell. For sufficiently high chopping frequency or for a sample with large lateral dimension, the signal is similar to its one‐dimensional counterpart. Departure from one‐dimensional theoretical predictions occurs at chopping frequency for which the lateral dimension is of the order of the thermal diffusional length of the gas. Spot size plays a relatively insignificant role in affecting the signal. These predictions as well as quantitative calculations based on the present theory are in agreement with several recently reported experiments.