Pesticides are known to be persistent in surface water and groundwater supplies and as a result, their existence in these water sources has been recognized as a major problem in many countries. The occurrence of these persistent pesticides in water bodies can also cause potential adverse public and environmental health effects. Among many water and wastewater treatment options, ozonation and ozone-based advanced oxidation processes, such as ozone/hydrogen peroxide, ozone/ultraviolet irradiation, and ozone/hydrogen peroxide/ultra violet irradiation, possess a high potential for degrading and detoxifying these pollutants in water and wastewater. In this paper, ozone based treatment of four major groups of pesticides, namely aniline-based compounds, pyridines and pyrimidines, triazines, and substituted areas, as well as that of several miscellaneous pesticides are reviewed. Degree of pesticide degradation, reaction kinetics, identity and characteristics of degradation by-products, and possible degradation pathways are covered and discussed.