Techniques for guard band utilization for wireless data communication are described. In at least some embodiments, guard bands can be leveraged to transmit wireless broadband data and/or other forms of wireless data. According to one or more embodiments, signal activity in a wireless channel that is adjacent to a guard band is monitored, e.g., while the guard band is being utilized for wireless data communication. In at least some implementations, if the signal activity exceeds a signal activity threshold, usage of the guard band channel can be adjusted to mitigate interference with signal activity in an adjacent channel.