This chapter uses data extracted from two recently compiled historical corpora of Australian English, the Corpus of Oz Early English (19th century) and AusCorp (20th century) to examine developments in ten morphosyntactic variables over the past two centuries. At the same time comparisons are drawn with British and American English, using data from ARCHER (A Representative Corpus of Historical English Registers). While Australian usage is found to have diverged from that of its British colonial parent, reflecting increasing independence from British linguistic norms, it has shifted towards that of American English – the new centre of gravity of grammatical change in English world-wide – which emerges as the most advanced variety on eight of the ten variables. Keywords: grammar; Australian English; diachronic; corpus; variation