Wireless sensors can be an extremely valuable enabling technology for structural health monitoring (SHM) applications. In the correct context, they can be used to dramatically decrease installation cost, reduce system weight, and even improve robustness. Wireless systems are inexpensive, easy to reconfigure, and contain the inherent capability to perform autonomous and embedded data processing. However, when considering implementation of a wireless component in an SHM system, it is also important to consider the limitations and relative disadvantages of the technology as well. In the incorrect context, wireless sensors will degrade performance, lose information, increase long-term costs, or even cause complete failure of the monitoring system. Wireless sensors can suffer from lower data transmission rates than their wired counterparts, are more prone to loss of information, and power supply is very frequently a critical limiting factor to their application. In this chapter, the relative advantages and disadvantages of wireless sensor technology for SHM applications in composite structures are discussed. As part of this discussion, the important core components of a typical wireless sensor are presented. In addition, strategies for overcoming the inherent disadvantages of the wireless approach are presented with special attention given to embedded computation and passive sensing. The goal of the chapter is not to provide an in-depth summary of all wireless sensing approaches to date (the approaches are many and varied and would warrant their own book), but to provide the reader with sufficient information to decide which wireless sensor technology, if any, might be most fitting for their application and what strategies they might consider to improve the performance and reliability of their monitoring application.