Micropollutants, encompassing a wide array of pharmaceuticals, personal care products, pesticides, and industrial chemicals, are increasingly recognized as a significant threat to aquatic ecosystems. This chapter analyzes micropollutant sources, distribution, and ecological impacts in freshwater and marine environments. The chapter explores how these contaminants affect biodiversity at multiple levels, from microorganisms and invertebrates to fish and higher trophic organisms. This chapter delves into specific case studies illustrating the sublethal effects of micropollutants, such as altered reproductive behaviors, immune system suppression, and disruptions in nutrient cycling. By surveying current research, we have identified the critical pathways through which micropollutants disrupt the ecological balance, leading to declining biodiversity and ecosystem services. Additionally, we have discussed the role of bioaccumulation and biomagnification in exacerbating these impacts across food webs. The chapter concludes with a discussion on the effectiveness of current regulatory frameworks and mitigation strategies to reduce micropollutant loads in aquatic environments, highlighting the need for innovative approaches to protect aquatic biodiversity.