Hydrogen sulfide is reported as one of the most common odor-producing compounds from sewage treatment plants. The literature review revealed that very little information is available on the emission of H2S from different units of sewage treatment plants. Besides, the removal efficiency as well as dispersion studies of H2S should be explored more. Therefore, the purposes of this study were to measure the emissions of H2S, evaluate the efficiency of odor control unit, and explore the dispersion potential of H2S from a sewage treatment plant in Muscat, Sultanate of Oman. Site survey analysis revealed four sources (tanker discharge area, grit/sand and fog removal channels, pre-aeration basin, and screen building) of H2S in the plant premises. Additionally, measurement analysis showed that the efficiency of odor control unit, which treated the emissions from all sources, except the tanker discharge facility, was 90.2%. The Gaussian plume dispersion modeling studies demonstrated that the allowable concentration of dispersed H2S (1 ppm) was observed > 30 m from the identified sources. Although the combined outlet of the odor control unit was greater than 1 ppm, the plant is complying with the current environmental specifications at the boundaries (≤ 1 ppm) set by the environmental authorities. Hence, a set of recommendations is suggested to improve the efficiency of the system to resolve the odor emission from the plant. [ABSTRACT FROM AUTHOR]