Nature-inspired adhesive systems draw inspiration from biological adhesion mechanisms to develop advanced artificial adhesives. Natural organisms, such as geckos, tree frogs, octopuses, and mussels, exhibit remarkable adhesion through unique micro- and nanostructures and chemical compositions. These natural adhesives rely on interactions like van der Waals forces, electrostatic forces, capillary forces, and chemical bonds. Researchers have studied these mechanisms to design artificial adhesives with tunable properties, including dry, wet, and underwater adhesives. These biomimetic adhesives are applied in various fields, such as biomedical engineering, soft electronics, and industrial manufacturing. Adhesion theories include models for solid-liquid, solid-solid, and solid-liquid-solid systems. The Cassie and Wenzel states describe wetting behaviors on rough surfaces, while the gecko model highlights the role of microstructures in enhancing adhesion. The Kendall model and JKR model are used to analyze solid-solid adhesion, considering factors like surface roughness and interfacial forces. For underwater adhesion, models like capillary force, suction, and adhesive secretion are employed, with the latter involving proteins that form strong bonds through oxidative covalent interactions. Characterization techniques assess adhesion strength and toughness, using parameters like contact angle hysteresis and sliding angle. These methods help quantify adhesion performance and guide the development of new materials. Recent advancements focus on smart adhesives with responsive properties, capable of adapting to environmental conditions. Challenges remain in achieving durable, reversible, and efficient adhesives, prompting ongoing research into biomimetic designs and novel materials. This review highlights the progress in understanding and applying nature-inspired adhesion mechanisms to create versatile and high-performance adhesives.Nature-inspired adhesive systems draw inspiration from biological adhesion mechanisms to develop advanced artificial adhesives. Natural organisms, such as geckos, tree frogs, octopuses, and mussels, exhibit remarkable adhesion through unique micro- and nanostructures and chemical compositions. These natural adhesives rely on interactions like van der Waals forces, electrostatic forces, capillary forces, and chemical bonds. Researchers have studied these mechanisms to design artificial adhesives with tunable properties, including dry, wet, and underwater adhesives. These biomimetic adhesives are applied in various fields, such as biomedical engineering, soft electronics, and industrial manufacturing. Adhesion theories include models for solid-liquid, solid-solid, and solid-liquid-solid systems. The Cassie and Wenzel states describe wetting behaviors on rough surfaces, while the gecko model highlights the role of microstructures in enhancing adhesion. The Kendall model and JKR model are used to analyze solid-solid adhesion, considering factors like surface roughness and interfacial forces. For underwater adhesion, models like capillary force, suction, and adhesive secretion are employed, with the latter involving proteins that form strong bonds through oxidative covalent interactions. Characterization techniques assess adhesion strength and toughness, using parameters like contact angle hysteresis and sliding angle. These methods help quantify adhesion performance and guide the development of new materials. Recent advancements focus on smart adhesives with responsive properties, capable of adapting to environmental conditions. Challenges remain in achieving durable, reversible, and efficient adhesives, prompting ongoing research into biomimetic designs and novel materials. This review highlights the progress in understanding and applying nature-inspired adhesion mechanisms to create versatile and high-performance adhesives.