Abstract: Since World War Two, the role of non profit think tanks in the United States has grown and diversified. Today, the United States' government and Congress is advised on many matters of policy‐making and implementation by such think tanks. The Westminster system of parliament, as practised in the United Kingdom, Canada, New Zealand, and Australia, has rarely provided a fertile ground for the creation and sustained existence of such privately operated institutions. Despite limited links with similar United States' organizations, the seeds have never really flourished outside the United States of America.Australian Commonwealth governments have been most antagonistic in this regard. On the other hand, management consulting companies, many of which have headquarters in the United States, lobbyists, and corporate representation flourish in the quasi‐corporatist political environment carefully constructed by the Australian Labor party (ALP) government since 1983. Policy‐related research divisions and statutory authorities have likewise grown in size and importance within the departmental agencies of government itself. Energy, agriculture, immigration, and social service research “arms” have been encouraged within the ministerial arena of policy analysis and advice. Especially important has been micro and macro‐economic research, urban and infrastructural planning, the Industry Commission, and the Bureau of Industry Economics, respectively.This paper will analyse the growth of these specialized forms of government think tanks, study the range of their ministerial advice, and speculate about their changing role in an increasingly “managerialist” type of Westminster‐style parliamentary setting.Sommaire: Aux États‐Unis, depuis la Seconde Guerre Mondiale, le rôle des groupes de réflexion à but non lucratif, ou think tanks, a pris de l'ampleur et s'est diversifié. Aujourd'hui, ces groupes prodiguent des conseils au gouvernement et au Congrès des États‐Unis sur de nombreuses questions de définition et de mise en oeuvre de politiques. Le système parlementaire de Westminster, tel que pratiqué au Royaume‐Uni, au Canada, en Nouvelle‐Zélande et en Australie, a rarement favorisé la création et l'existence de telles institutions exploitées par le secteur privé. Malgré certains liens limités avec des organisations américaines similaires, elles ne se sont jamais vraiement épanouies à l'extérieur des États‐Unis.