<p>Organophosphate and organochlorine pesticides (OPPs and OCPs) have extensively been used for plant protection in agriculture. Being highly persistent and toxic, their indiscriminate use over the years has posed a severe threat to human health and ecological stability. These are labelled as hazardous classes of chemical compounds by the WHO. Though many of these pesticides are slowly phased out in most developed countries, these are still in use in most developing countries amidst a lack of stringent regulations, making it necessary to monitor their concentration levels. Complex matrix coupled with low concentration levels make pesticide monitoring quite challenging. Though sensitive and highly accurate, the currently established detection methods are time-consuming and quite expensive, rendering them inaccessible for wide-scale routine analysis. Nanomaterials (NMs), with their exceptional physicochemical properties, have emerged as promising tools for detecting OPPs and OCPs. Unusual structural manipulations in NMs lead to them exhibiting distinct electrical and optical properties. This review details the hazardous impact of some commonly used OPPs and OCPs. It explores the use of functionalized nanomaterials, including metal nanoparticles, nanozymes, nanocomposites, carbon-based nanostructures and metal–organic frameworks in their detection. The study provides a comprehensive insight into the role of nanomaterials in achieving lower detection limits up to the nanomolar range through enhanced signal responses in spectroscopic, electrochemical and optical techniques and potential for on-site analysis. Challenges associated with these methods and future directions for developing even more robust and practical nanomaterial-based sensors for organophosphate and organochlorine pesticide detection have been discussed.</p> Graphical Abstract <p></p>