This paper documents the discovery of phytoliths (siliceous plant fossils) from late Devonian, Permian and Triassic Beacon Supergroup strata at Mts. Crean and Feather in the Transantarctic Mountains, Antarctica. The five phytolith forms documented here are among the oldest phytoliths reported to date. The period when these phytoliths were deposited represents the time when Gondwana land plants were evolving into present day vegetation patterns. The phytoliths identified in this study have the potential to trace Beacon Supergroup sediments and also to provide phytogeographical information documenting plant taxa that once grew on the Antarctic craton.