In the present work, the piezoelectric properties of TlIn[Formula: see text]Ga[Formula: see text]Se2 single crystals are investigated. Single crystals were grown by the Bridgman–Stockbarger method. The results show that when periodic mechanical vibrations are excited in these crystals, the electrical conductivity is modulated at the same frequency. Measurements of the amplitude values of the piezoconductivity at the same degree of deformation in the dark and under different illumination revealed the presence of a linear relationship between them. The level of the piezosignal also changes linearly depending on the strength of the magnetic field. Thus, TlIn[Formula: see text]Ga[Formula: see text]Se2 crystals have a potential prospect of application in the field of highly sensitive magnetic and light sensors.