The story of legislative autonomy in the Dominions typically ends with the incorporate of the Statute of Westminster. This overlooks the subsequent struggles within the Dominions to establish some form of parliamentary supremacy as an internal norm within their constitutional structures. This was particularly noticeable in those Dominions which possessed a unitary form of government, the Irish Free State, South Africa and New Zealand. This paper aims to trace the development of this idea and the institutional constraints which were encountered within the constitutional systems. The insights of these institutional structures will be contrasted with Australia and the short-lived South Asian Dominions.