The structures and types of known categories of surfactants have been discussed in brief, besides some new categories of surfactants, such as gemini, natural and biosurfactants and some specially designed ones like polymeric, viscoelastic, magnetic and fluorinated surfactants. Introductory information on some fundamental properties shown by surfactant systems, such as critical micelle concentration (CMC), Kraft point (KP), cloud point (CP), solubilisation parameters, hydrophile–lipophile balance (HLB), hydrophilic-lipophilic deviation (HLD) as well as microemulsion formation, has been provided. Applications of surfactants in some chemical and petrochemical industries have been discussed. In chemical industries, specifically their applications as corrosion inhibitors, for waste water treatment, in cosmetic industries and in pharmaceutical industries have been described. In petrochemical applications, their utilisation for alternative fuel production, enhanced oil recovery, demulsification of crude oil emulsions, oil sorbent removal and remediation and for water-based drilling fluid production has been discussed. A clear notion regarding the multifaceted applications of surfactants in emerging and established areas has been presented in the present chapter, which can trigger further innovative applications of surfactants.