Biosorption, as a cost-effective technology for the removal of soluble heavy metals and organics from aqueous solutions, has been extensively studied, and most biosorption research mainly focused on the process isotherms, kinetics and thermodynamics. Thus, this paper attempted to offer a better understating of representative biosorption isotherms, kinetics and thermodynamics with special focuses on theoretical approaches for derivation of combined Langmuir–Freundlich isotherm as well as the pseudo-first- and second-order kinetic equations and general rate law equation for biosorption. Meanwhile, some potential problems encountered in biosorption research were also discussed.