For utilization in environments where radiation causes concern, a material's photogeneration coefficient proves essential for device designers. To extract this parameter for gallium oxide, which exhibits higher breakdown voltage characteristics compared with other commonly used semiconductor materials, making it desirable for high‐power applications, Schottky diodes receive high‐dose‐rate radiation from an electron linear accelerator. Monitoring photogenerated charge versus dose rate reveals a photogeneration coefficient of 2.4 × 1015 pairs (cm−3‐rad(Si)−1) for epitaxially grown β‐phase gallium oxide.