This comprehensive review explores the advancements in nanomaterials (NMs) for nanosensors, highlighting their unique properties and applications across various domains. The review covers the classification of NMs, including carbon-based, metal-based, and semiconductor-based materials, and discusses their exceptional properties such as high thermal and electrical conductivity, large surface area-to-volume ratio, and biocompatibility. It delves into the fabrication methods, characterization techniques, and sensing mechanisms of NMs, emphasizing their use in healthcare, environmental monitoring, industrial processes, and security. The review also examines the integration of machine learning techniques to enhance sensor performance and addresses key challenges such as robustness, biocompatibility, and scalable manufacturing. Additionally, it provides insights into the historical development of nanotechnology, from ancient times to modern advancements, and discusses the future prospects and potential developments in nanomaterial-based nanosensors.This comprehensive review explores the advancements in nanomaterials (NMs) for nanosensors, highlighting their unique properties and applications across various domains. The review covers the classification of NMs, including carbon-based, metal-based, and semiconductor-based materials, and discusses their exceptional properties such as high thermal and electrical conductivity, large surface area-to-volume ratio, and biocompatibility. It delves into the fabrication methods, characterization techniques, and sensing mechanisms of NMs, emphasizing their use in healthcare, environmental monitoring, industrial processes, and security. The review also examines the integration of machine learning techniques to enhance sensor performance and addresses key challenges such as robustness, biocompatibility, and scalable manufacturing. Additionally, it provides insights into the historical development of nanotechnology, from ancient times to modern advancements, and discusses the future prospects and potential developments in nanomaterial-based nanosensors.