The Ga(1−x)AlxAs ternary semiconductor alloys have important applications for optoelectronic devices such as lasers and solar cells; hence electrical properties have been investigated extensively. However, little information is available about the behavior of Zn in metalorganic chemical vapor deposition (MO‐CVD)Ga(1−x)AlxAs. In this paper the electrical properties of Zn‐doped,p‐type Ga(1−x)AlxAs films (0⩽x⩽1.0) grown by MO‐CVD on GaAs:Cr substrates were studied using Hall measurements over a wide range of temperature (77 to 420 °K). The electrical activation energies were determined by measuring the variation of the carrier concentration of Ga(1−x)AlxAs films with temperature. The results indicate that activation energies increase with increasing Al composition (from 23∼26 meV forx= 0 to 140 meV forx= 1.0). The experimental results have been compared with theoretical data calculated from the modified hydrogenic model, and agreement is excellent forx⩽0.5.