The growing global population and the increasing demand for food security necessitate the development of innovative agricultural technologies. One significant challenge in modern agriculture is the early detection and management of abiotic stress in crops, which includes factors such as drought, salinity, extreme temperatures, and heavy metals. These stressors can severely impact crop yield and quality, necessitating timely intervention. This chapter explores the burgeoning field of nanotechnology-based biosensors as a revolutionary approach for the early detection of abiotic stress in crops. Nanotechnology offers unique advantages, including high sensitivity, specificity, and rapid response times, making it ideal for biosensing applications. We discuss various types of nanomaterials (NMs), such as carbon nanotubes, quantum dots, and metallic nanoparticles (NPs), which are utilized in constructing biosensors. These NMs enhance the performance of biosensors by providing increased surface area, improved electrical conductivity, and tailored optical properties. The chapter delves into the mechanisms by which nanotechnology-based biosensors detect abiotic stress markers, such as reactive oxygen species, stress-related proteins, and phytohormones. Furthermore, we address the integration of these biosensors with wireless networks and data analytics platforms for comprehensive crop management systems. Moreover, current limitations and future perspectives of nanotechnology-based biosensors have been discussed in the agricultural practices, considering factors such as scalability, cost, and environmental impact. By harnessing the power of nanotechnology, these biosensors represent a promising tool for enhancing crop resilience and productivity in the face of climatic and environmental challenges.