Abstract: In Australia, the role of interpreting the Constitution is ultimately for the High Court, but some ‘space’ remains for its interpretation by the Parliament. Space exists in rare cases where the Court defers to the judgment of Parliament or where a non-justiciable question arises. In these cases, Parliament must consider constitutionality without assistance from the courts: ‘parliament-centred interpretation’. In the predominance of cases, while the final word on constitutional interpretation remains with the courts, we argue that ‘best practice’ requires individual parliamentarians to consider the constitutionality of Bills using ‘court-centred interpretation’. We demonstrate our argument using two case studies: the proposed amendments to the Marriage Act 1961 (Cth) to allow for same-sex marriage, and the passage of legislation following Williams v Commonwealth.