Final obstruent devoicing is common in the world’s languages and constitutes a clear case of parallel phonological evolution. Final obstruent voicing, in contrast, is claimed to be rare or nonexistent. Two distinct theoretical approaches crystalize around obstruent voicing patterns. Traditional markedness accounts view these sound patterns as consequences of universal markedness constraints prohibiting voicing, or favoring voicelessness, in final position, and predict that final obstruent voicing does not exist. In contrast, phonetic-historical accounts explain skewed patterns of voicing in terms of common phonetically based devoicing tendencies, allowing for rare cases of final obstruent voicing under special conditions. In this article, phonetic and phonological evidence is offered for final obstruent voicing in Lakota, an indigenous Siouan language of the Great Plains of North America. In Lakota, oral stops /p/, /t/, and /k/ are regularly pronounced as [b], [l], and [ɡ] in word- and syllable-final position when phrase-final devoicing and preobstruent devoicing do not occur.