Lambda, the symbol of the Identitarian movement/Identitarianism used primarily in Europe by Generation Identity and occasionally other countries, intended to commemorate the Battle of Thermopylae.
Identity is the most important question to answer. Who are we racially? Who are we historically? Who are we in terms of our experience? Who are we in terms of our community?
~ Richard Spencer

The Identitarian movement or Identitarianism is a post-World War II European far-right political ideology asserting the right of Europeans and peoples of European descent to culture and territories claimed to belong exclusively to them. Originating in France and building on ontological ideas of modern German philosophy, its ideology was formulated from the 1960s onward by essayists such as Alain de Benoist, Dominique Venner, Guillaume Faye and Renaud Camus, considered the movement's intellectual leaders.

While on occasion condemning racism and promoting ethnopluralist society, it argues that particular modes of being are customary to particular groups of people, mainly based on ideas of thinkers of the German Conservative Revolution, in some instances influenced by Nazi theories, through the guidance of European New Right leaders.

Some Identitarians explicitly espouse ideas of xenophobia and racialism, but most limit their public statements to more docile language. Some among them promote the creation of white ethno-states, to the exclusion of migrants and non-white residents. The Identitarian Movement has been classified by the German Federal Office for the Protection of the Constitution in 2019 as right-wing extremist.

The movement is most notable in Europe, and although rooted in Western Europe, it has spread more rapidly to the eastern part of the continent through conscious efforts of the likes of Faye. It also has adherents among North American, Australian, and New Zealander white nationalists. The United States–based Southern Poverty Law Center considers many of these organisations to be hate groups.

The movement has been described as being part of the global Alt-Right, or as the European counterpart of the American alt-right. Hope Not Hate (HNH) has described Identitarianism and the alt-right as "ostensibly separate" in origin, but with "huge areas of ideological crossover". Many white nationalists and alt-right leaders have described themselves as Identitarians, and according to HNH, American alt-right influence is evident in European Identitarian groups and events, forming an amalgamated "International Alternative Right".

Figures within the Identitarian movements and alt-right often cite Nouvelle Droite founder Alain de Benoist as an influence. De Benoist rejects any alt-right affiliation, although he has worked with Richard B. Spencer, and once spoke at Spencer's National Policy Institute. As Benoist stated, "Maybe people consider me their spiritual father, but I don't consider them my spiritual sons".

According to Christoph Gurk of Bayerischer Rundfunk, one of the goals of Identitarianism is to make racism modern and fashionable. Austrian Identitarians invited radical right-wing groups from across Europe, including several neo-Nazi groups, to participate in an anti-immigration march, according to Anna Thalhammer of Die Presse. There has also been Identitarian collaboration with the white nationalist activist Tomislav Sunić.