This article deals with the main cultural and ideological factors have affected Iran’s transnational interactions during last century. I emphasize nationalism and Islamism as two key independent variables. Three faces of nationalism have been emerged in Iran since the Constitutional Revolution at the outset of the 20^th century: the Persian nationalism in the Pahlavi rule, the liberal nationalism during Mosaddeq’s movement, and the religious nationalism after Islamic Revolution. Each of them has influenced Iran’s Foreign policy in a special way. While nationalism was a dominant ideological discourse in Iran’s foreign policy before 1979 Islamic Revolution, the Islamic idealism became the leading discourse in the post- Islamic revolution era. Therefore, Islamic Republic of Iran has always opposed the unjust international order and has challenged interventionist foreign policy of major powers of the world