Abstract: The emission of volatile organic compounds is a focus in environmental pollution problems at present. Monocyclic aromatic hydrocarbons are one of the most important components, which are represented by benzene, toluene, ethylbenzene and o-, m-, p-xylene (BTEX). Affected by anthropogenic activities, BTEX were widely detected in the atmosphere, soil, surface runoffs, underground runoffs and the ocean. Their environmental and ecological toxic effects have been widely concerned. The present study overviewed the distributions, sources and fates of BTEX in the oceanic mediums, including atmosphere, seawater, sediments and living organisms. Previous studies showed that the concentrations of BTEX in marine environment have a wide range of variation, and their distributions show a decreasing trend from the inshore to the offshore. The main source of BTEX is anthropogenesis, that is, the ocean is an important sink of terrigenous BTEX. The sea-air exchange and biodegradation are considered to be the main removal pathways of BTEX. In addition, the ecological and atmospheric effects of BTEX in the ocean are discussed. Due to their biological toxicities, BTEX might threaten the survival and reproduction of marine organisms and damage the marine ecosystem. Atmospheric BTEX can affect atmospheric oxidation capacity and play important roles in forming the ozone and secondary organic aerosols. Although some knowledge have been obtained in the study of marine BTEX, the source analysis, migration and transformation processes and biological toxicity mechanism of BTEX in different marine environments need to be studied systematically for further understanding of the biogeochemical processes and environmental effects of BTEX.