Stop consonant voice onset time (VOT) was examined in a typological survey of over 100 languages. Within broadly defined laryngeal categories (long-lag, short-lag, and lead voicing), VOT means were found to vary extensively. Importantly, the means for members of the same laryngeal series did not vary independently but instead were highly correlated across languages. The strong linear relations identified here cannot be reduced to previously reported ordinal relations, and provide evidence for a uniformity constraint on phonetic realization: within a language, each laryngeal specification must be realized in approximately the same way across stops of different places of articulation.