The past two decades have witnessed a growing scholarly interest in the role that “ethnic diasporas” play in the formulation of America’s foreign policy. While the connection between these ethnic groupings and the policy process is not anything new in American political life, the systematic study of that connection is of relatively recent vintage. There are two chief reasons for this. First, changes in American demography since the 1970s have led to a fascination with issues related to “multiculturalism” and ethnic “identity”—in the context not only of domestic public policy, but also of foreign policy. In the case of the latter, an outpouring of articles and books has appeared dedicated to the phenomenon of ethnic “lobbying,” construed widely enough so as to include discussions of the “ethnic vote.” In addition, changes in the external environment set in motion by the ending of the Cold War and the demise of the Soviet Union have put a premium upon such new relatively new categories of analysis as “ethnic conflict” and diasporas. Widespread stories about its “decline” to the contrary notwithstanding, America remains the most powerful state in the international system; thus, it offers ethnic diasporas the promise of exerting outsized influence should they be able to make their preferences become Washington’s preferences. This article surveys leading bibliographical sources pertaining to these various themes, embracing as well the normative debates they have engendered. Also included in this article are a set of references to a trio of very significant historical cases of ethnic “politicking” in US foreign policy, for, although the systematized study of the phenomenon may be fairly recent, the phenomenon is nearly as old as American foreign policy itself. Accordingly, three “classical cases” will be discussed: the Irish Americans, the German Americans, and the Anglo-Americans. Finally, the article surveys recent writings on contemporary cases in which ethnic diasporic activism has been said to have influenced the shaping of American foreign policy toward one region in particular (the “greater” Middle East) as well as toward regional dilemmas elsewhere (including Europe, Africa, and Latin America).