The advent of nanotechnology has brought about various developments in the fields of drug, food sectors, agriculture, and industrial work. The nanomaterials have unique physicochemical, and mechanical properties leading to a significant advancement in monitoring and managing agricultural processes. Nanotechnological applications have resulted in the development of smaller-size structures called nanosensors. These nanosensors interact with the targeted substance on a nanoscale, producing detectable signals that can be analyzed through various methods. Metal oxide-based nanosensors are a promising tool because of their high selectivity, sensitivity, and stability. Different metal oxides such ZnO, TiO2, SnO2, and Fe2O3 are used in biosensing technologies for diagnosing different parameters like environmental conditions, moisture content, pesticides, plant pathogen, pH levels, and soil nutrients. There are several applications for these metal oxide nano biosensors in farming operations. Hence, utilizing these nanosensors permits environmentally friendly and smart farming practices. This chapter will give us an overview of metal oxides-based nanosensors, their types, and their applications in agriculture. Various advantages and limitations are discussed thoroughly in this chapter to provide useful insights into nano biosensors in modern agricultural systems.