Abstract This acoustic study investigated the extent and nature of vowel-to-vowel coarticulation in English trisyllabic utterances (/bV1bəbV3b /) where both V1 and V3 were either /a/ or /i/. Primary stress was assigned to either the first or third syllable, and secondary stress was assigned to the other syllable. The study revealed considerable variability among the four speakers in the systematic effects of non-adjacent vowels on one another. The most important result is that coarticulatory effects can, in some instances, extend beyond the bounds that previous research had assumed; both carry-over and anticipatory effects extend from one full vowel, through the medial schwa, and into the midpoint of the other full vowel. In fact, for one speaker, effects of V3 can be seen as early as V1 onset of /a/. This result indicates that the foot does not define the domain over which coarticulatory effects operate. Finally, this study found no evidence of greater carry-over than anticipatory effects.