This article reviews the role phonology plays in phonetic changes. After first establishing what kinds of changes qualify as phonetic changes for the purposes of discussion, and laying out the theoretical outlook that is adopted here, I review the most obvious cases in which phonology plays a role in phonetic change. These include (a) the way phonological contrast can lead to phonetic dispersion, (b) the way phonological natural classes can define a set of segments to undergo a parallel phonetic shift, and (c) how phonological biases may lead to instances of underphonologization. Throughout, I discuss alternative approaches to these phenomena.