One of the biggest challenges facing the widespread implementation of wireless sensor networks is wireless interference and radio-frequency (RF) spectrum crowding. Even today, wireless networks are already straining under society’s relentless demand for higher data rates and constant connectivity. For wireless sensor networks to become a reality, research on increasing network capacity and allocating spectral resources must necessarily involve new techniques for handling wireless interference scalably and efficiently. This chapter focuses on analog interference cancellation using optical signal processing as a path towards operating in the presence of wireless interference. Canceling interference before it enters a receiver allows wireless sensor networks to conserve scarce spectral resources and relax system requirements, resulting in robust operation, increased battery life, and reduced size and cost. Through its unique physics, optics enables new RF functionalities that are extremely valuable to canceling interference in the RF front-end, chief among them being wide processing bandwidth. The wideband nature of optics is key to anticipating the rise in data rates, bandwidths, and channel counts of future networks, and endows optics with the potential to realize true multiband radio transceivers. Our goal in this chapter is to present an overview of optical-based RF interference cancellation and discuss the key characteristics that make optics an outstanding technology platform for the job.We then show several system architectures and a sample of their experimental performance.We leave the readers with a discussion on the future prospects for this technology, focusing specifically on photonic integrated circuits.