Synthetic surfactants are among the chemicals that are produced and consumed in the largest volumes in the world (more than 10 million tons per year), due to their variety of applications, mainly as key ingredients in detergents and cleaners but also as additives in paints, pesticides, personal care products, etc. In spite of the high removal efficiences of surfactant residues in sewage treatment plants (STP), significant amounts of these chemicals reach aquatic ecosystems via direct discharges of treated or non-treated wastewaters, or indirect discharges through rivers, where they are present dissolved or associated with particulate material. Therefore, particular attention has been given to the environmental analysis of anionic and non-ionic surfactants (90% of the overall production. Our main objective in this work was to detect the presence and compare the distribution of the most world-wide used non-ionic (alcohol polyethoxylates, AEOs, and nonylphenol polyethoxylates, NPEOs) surfactants, and an important group of nonionic synthetic water-soluble polymers of ethylene oxide, polyethylene glycols (PEGs), which are also used in a wide range of applications (e.g., antifreeze agents, cosmetics) as well as the main precursors / degradation products of AEOs, in waters and sediments from Mar Menor Lagoon (SE Spain). Under our knowledge, some of the data shown here are among the first even reported on the environmental distribution of PEGs in aquatic systems.