Speech animation may be performed using visemes with phonetic boundary context. A viseme unit may comprise an animation that simulates lip movement of an animated entity. Individual ones of the viseme units may correspond to one or more complete phonemes and phoneme context of the one or more complete phonemes. Phoneme context may include a phoneme that is adjacent to the one or more complete phonemes that correspond to a given viseme unit. Potential sets of viseme units that correspond with individual phoneme string portions may be determined. One of the potential sets of viseme units may be selected for individual ones of the phoneme string portions based on a fit metric that conveys a match between individual ones of the potential sets and the corresponding phoneme string portion.