Abstract Wireless sensor networks are collaborative and low-cost infrastructures composed of sensing, computing, and communication devices that are aimed at collecting a variety of measurements, which brings significant advantages over traditional wired communication technologies. The smart grid (SG), initially defined as an advanced metering infrastructure to improve energy efficiency, has new requirements and demands that stimulate the researchers to rethink and expand its perceived scope. The communication architecture of the future SG is still being defined, therefore multiple communication technologies and standards could coexist in different parts of the system. One of these technologies is identified at nanoscale, which exploits the unique properties of novel nanomaterials, such as nanosensors, nanoantennas, and nanotransceivers, leading to the concept of wireless nanosensor networks (WNSNs). The following chapter provides an overview of the SG concept, with focus on WNSNs, their current solutions, and future developments.