With the development of modern industry and modern economies, environmental problems, especially water pollution and water scarcity, have become the most serious global challenges. In dealing with these challenges, various kinds of functionalized materials and devices are purposefully developed, fabricated, and utilized. It is clear that smart materials have not only provided effective strategies for solving environmental problems, but have also exhibited unprecedented advantages over traditional materials by integrating multifunctions and/or processes into one advanced device/material. In this book, we will present a broad collection of bioinspired smart materials and systems that are used in environmental problem solving. The topics of these chapters span from bioinspired fog collection, self-healing materials, responsive particle-stabilized emulsions, smart draw solutions in forward osmosis, slippery coating, insightful analysis of problems and opportunities for hydrophobic surfaces applied in real conditions, to superwetting materials for oil–water separation.