Aviation products widely use metallic and composite structural bonding. Applications include general aviation wings and fuselage splices, rotorcraft blades and airframe stiffeners, transport airplane stiffeners and control surface details, military fighter wing-to-body joints, and advanced air mobility vehicle stiffeners and splices. Bonded repairs are also common across all products. Civil and military aviation regulations require strict process definition and control. Like composite materials, adhesives are not approved independent of a product but instead are certified as part of the overall structural substantiation. Bonded structures are a system defined by multiple elements, not just the adhesive, which requires bond process qualification. This chapter discusses bond-related certification requirements, defines bonding systems, reviews bonding applications and service experience in aviation, and provides best practice protocols for designing, certifying, and substantiating bonded structures and repairs.