The stochastic environmental loading present in potential offshore wind farm locations leads to high costs for the turbine's support structure. As a result, it is important to determine the contribution each damping source on these types of loading. The least is known about foundation damping, therefore it is conservatively neglected in structural design. A parameter study will be presented to show how foundation damping affects structural demands over a variety of wind, wave, and operating conditions. Given that fatigue analysis is important for ensuring the design life of OWTs, the effective contribution of damping on fatigue damage accumulation will also be estimated. Examining the sensitivity of structural loading to damping may allow foundation damping to be advantageously incorporated into design guidelines, potentially leading to a more efficient OWT design and reduction in the large cost of the support structure.