We provide an empirical study of the High Court’s citation to case law and secondary sources at decade intervals between 1905 and 2015. We document trends in the number and type of citations over time, both for the Court as a whole and for the individual Justices. We find that in each of the sample years between 1905 and 1975, the Court cited relatively few authorities and for most of this period the majority of citations were to the Court’s own previous decisions or to decisions of the English courts. However, over the last four sample years — 1985, 1995, 2005 and 2015 — the Court cited more authority. The Court cited an increasing proportion of its own previous decisions over this period as well as a higher proportion of authority from a more diverse range of sources, including secondary sources, largely at the expense of citations to English cases. We conclude that this reflects the emergence of a distinct Australian common law with the High Court as its final arbitrator.