Globally, national curriculum policies are up for renegotiation. These negotiations are shaped by international and national top-down accountability regimes, and an increasing turn towards curriculum centralization and standardization. The new Australian Curriculum (AC) is no exception. The AC is an important educational policy event, one in which understandings about teacher professional authority is being redefined. In this paper, we examine how judgements about teachers' professional authority are used to defend, promote and explain the AC. Drawing on an analysis of policy documents and interviews with high-level policy-makers, we argue that the AC is opening space in the policy field to reposition teachers' work by promoting a view of teachers' professional authority as constrained and defined through the written curriculum documentation.