Adsorption is among the various available water treatment technologies that employ solid adsorbents and has the potential to be one of the most efficient methods for treating and removing contaminants from wastewater. The adsorption-based removal of a plethora of pollutants has garnered widespread attention owing to its cost-effective nature and the availability of diverse types of adsorbents. The adsorbents could also be specifically designed to remediate a special class of pollutants for enhanced selectivity and removal efficiency or could be designed for improved porosity and surface functionality for adsorbing different pollutants, based on the end use. The adsorption process encompasses various processes such as physisorption, chemisorption, and electrostatic interactions as the underlying mechanisms. Here, we discuss about hydrogen bonding, hydrophobic interactions, van der Waals forces, electrostatic interactions, π–π interactions, n–π interactions, and π–π electron donor–acceptor (EDA) interactions. This chapter also discusses the effect of different surface functional groups, surface charge, ionization state, and the degree of electrostatic interactions, as well as environmental conditions (such as pH, temperature) on the adsorptive removal of various pollutants. The thermodynamics and kinetics governing the adsorption have also been intricately discussed. Thus, it could be possible to build highly effective adsorbents and optimize the adsorption process for environmental remediation by comprehending all these mechanisms along with the dependent parameters.