This dissertation analyses the idea that parliament controls public money in parliamentary constitutional systems of government. That analysis proceeds through an historical and contemporary examination of the way legal practices distribute authority over public money between different institutions of government. The legislative and judicial practices concerning taxation, public expenditure, sovereign borrowing, and the government financing activities of central banks are selected for close attention. The contemporary analysis focuses on the design and operation of those legal practices in the United Kingdom and the Commonwealth of Australia, in the context of the boom-bust-recovery economic conditions experienced between 2005 and 2016. The dissertation's ultimate claims are explanatory: that "parliamentary control" is a poor explanation of the distribution of financial authority in parliamentary systems of government and should be jettisoned in favour of an idea of "parliamentary ratification". An empirically engaged methodology is adopted throughout the dissertation and (historical and contemporary) public sector financial data enrich the legal analysis. The dissertation acknowledges the impact of, but remains agnostic between, different economic and political perspectives on fiscal discipline and public financial administration. The dissertation makes a number of original contributions. It provides a detailed examination of the historical development, legal operation and constitutional significance of annual appropriation legislation, and the legal regimes governing sovereign borrowing and monetary finance. It also analyses the way that law interacts with government behaviour in situations of economic emergencies (focusing on the Bank of England's public financing activities since 2008), and the institutional and doctrinal obstacles facing judicial involvement in disputes concerning public finance (focusing on the Australian judiciary's recent engagements with public expenditure legislation).