Neuroactive chemicals are the largest group of micropollutants present in European rivers. There is increasing concern about the behavioral effects of these neuroactive chemicals on aquatic wildlife, potentially resulting in detrimental effects on individual, population, and community levels of ecological organization. This Special Issue, titled "Behavioral Impairment in Aquatic Organisms Exposed to Neurotoxic Pollutants", presents original research and review articles addressing behavioral impairment induced by different aquatic invertebrate and vertebrate species to neuroactive chemicals. The selected studies include different methodological approaches, such as multi-compartment, automated plug and play, and homemade setups systems. We believe that this collection provides essential information regarding research and challenges on the behavioral ecotoxicity of invertebrate and vertebrate aquatic organisms, as well as the molecular mechanisms behind these effects.