This PhD thesis asks how ‘neo-liberal’ was the Thatcher government? Existing accounts tend to characterise neo-liberalism as a homogeneous, and often ill-defined, group of thinkers that exerted a broad influence over the Thatcher government. This thesis - through a combination of archival research, interviews and examination of ideological texts - defines the dominant strains of neo-liberalism more clearly and explores their relationship with Thatcherism. In particular, the schools of liberal economic thought founded in Vienna and Chicago are examined and juxtaposed with the initial neo-liberals originating from Freiburg in 1930s and 1940s Germany. Economic policy and deregulation were the areas that most clearly linked neo-liberal thinking with Thatcherism, but this thesis looks at a broad cross section of the wider programme of the Thatcher government. This includes other domestic policies such as education and housing, as well as the Thatcher government’s success in reducing or altering the pressures exerted by vested interests such as the trade unions and monopolies. Lastly, while less associated with neo-liberal theory, foreign policy, in the area of overseas aid, is examined to show how ideas filtered into the international arena during the 1980s. Although clearly a political project, the policies of Thatcherism, in so far as they were ideological, resonate most with the more expedient, or practical, Friedmanite strain of neo-liberalism. This encapsulated a willingness to utilize the state, often in contradictory ways, to pursue more marketorientated policies. As such, it sat somewhere between the more rules-based ordoliberalism and the often utopian Austrian School.