The overuse of pesticides in modern agriculture has prompted serious concerns about food safety, environmental sustainability, and public health. The rapid and reliable detection of pesticide residues is critical for avoiding dangerous exposure and maintaining regulatory compliance. Conventional detection techniques, such as gas chromatography (GC) and liquid chromatography-mass spectrometry (LC-MS), have excellent accuracy but are time-consuming, expensive, and necessitate complicated laboratory infrastructure. Nanosensors have emerged as a cutting-edge technology for quick, low-cost, and extremely sensitive pesticide residue quantification. These sensors use nanomaterials, including metal nanoparticles (NPs), carbon-based nanostructures, and quantum dots (QDs), to improve signal detection via electrochemical, optical, and biosensing approaches. Their unique qualities, including high surface area, tunability, and strong interaction with target molecules, allow for precise and real-time detection of ultra-low pesticide doses. Recent advances in nano-enabled electrochemical sensors, fluorescence-based platforms, and surface-enhanced Raman spectroscopy (SERS) have made it possible to detect pesticides in food, water, and environmental samples. This review delves into the most recent advances in nano-sensor technology for pesticide detection, with a focus on sensor design, operating principles, real-world applications, and future directions.