GaAs wafers are essential for the production of GaAs semiconductor chips, which have a wide range of applications in manufacturing electronic devices, including power electronics, photovoltaic cells, sensors, and detectors. The demand for GaAs wafers is steadily increasing due to technological advances and growing environmental awareness, posing new challenges for the industry. During the production of GaAs wafers alone, 15% of the gallium originally used is lost during the process as liquid and solid production waste. These wastes can be considered as secondary raw materials, which should be recycled. In this study, the possibility of bioleaching the gallium from a metal hydroxide sludge, a waste product from the GaAs-wafer production, was investigated. Therefore, oxidative and reductive bioleaching strategies with 5% (w/v) metal hydroxide sludge were tested. The results showed that during oxidative bioleaching of the metal hydroxide sludge nearly 90% Ga was leached after 6 days and for the reductive bioleaching 87% Ga was leached after 8 days. However, reductive bioleaching proved to be a more attractive approach, as the treatment of the leaching solution would be more sustainable. This study demonstrates the potential of bioleaching for the recycling of gallium from waste products resulting from GaAs wafer production.