The purpose of our study is to show that phonological knowledge is an important basis for making predictions during speech perception. Taking the phonological constraint in English that coda obstruent clusters agree in their value for voicing, we conducted two experiments using vowel–stop–fricative sequences, where the task was to identify the fricative. Stimuli included sequences that were either congruent or incongruent. Consistent with models of featural underspecification for voiceless obstruents, our results indicate that only voiced stops induced predictions for an upcoming voiced fricative, eliciting processing difficulty when such predictions were not met. In contrast, voiceless stops appear to induce no equivalent predictions. These results demonstrate the important role of abstract phonological knowledge in online processing, and the asymmetries in our findings also suggest that only specified features are the basis for generating perceptual predictions about the upcoming speech signal.