Gemini surfactants represent an innovative class of surface-active agents formed by covalently linking two conventional single-chain surfactant molecules through a spacer group at their hydrophilic head groups. This unique "twin-head twin-tail" molecular architecture enables tighter molecular packing at interfaces, demonstrating surface activity up to hundreds of times greater than traditional surfactants. These surfactants exhibit extremely low critical micelle concentrations, superior wetting and emulsifying capabilities, and distinctive rheological properties, achieving effects at low concentrations that require high concentrations of conventional surfactants. Major structural variants include alkane chain systems, aromatic spacers, and heteroatom-containing linkers. They find applications in high-efficiency detergents, personal care products, nanomaterial templating, gene transfection, and enhanced oil recovery. Their exceptional performance efficiency and molecular design flexibility make them a significant developmental direction in surfactant science.