Thermophilic bacteria represent a powerful class of extremophiles whose ability to thrive at elevated temperatures makes them indispensable to modern biotechnology. The Arabian Gulf characterized by extreme heat, geothermal systems, hot springs, oil reservoirs, and hypersaline habitats hosts a rich yet understudied reservoir of these organisms. This review consolidates current insights into the diversity, ecological niches, and biotechnological relevance of thermophilic bacteria isolated from the region. Dominant genera such as Bacillus, Geobacillus, Thermus, Anoxybacillus, and Brevibacillus exhibit remarkable physiological and molecular strategies that enable survival under intense thermal, saline, and pH stress. Their capacity to produce thermostable enzymes, including proteases, amylases, lipases, cellulases, and DNA polymerases, positions them as high-value contributors to sectors spanning bioenergy, pharmaceuticals, food processing, agriculture, and environmental remediation. Beyond enzyme production, emerging applications such as antimicrobial compound discovery, hydrocarbon bioremediation, wastewater treatment, and sustainable bioprocessing highlight the region’s untapped biotechnological potential. However, systematic exploration remains limited, hindered by sparse isolation efforts, incomplete physiological profiling, and a lack of genomic and omics-driven studies. The review underscores the need for integrated approaches that merge classical microbiology with advanced molecular and systems-level tools. Collectively, thermophilic bacteria from the Arabian Gulf constitute a promising yet underutilized biological resource poised to drive sustainable industrial innovation and environmental solutions.