Neo-fascism is a post-World War II far-right ideology which includes significant elements of fascism. Neo-fascism usually includes ultranationalism, ultraconservatism, racial supremacy, right-wing populism, authoritarianism, nativism, xenophobia, and anti-immigration sentiment, as well as opposition to social democracy, parliamentarianism, Marxism, communism, socialism, liberalism, neoliberalism, and liberal democracy.

According to Jean-Yves Camus and Nicolas Lebourg, neo-fascism emerged in 1942 after Nazi Germany invaded the USSR and decided to reorient its propaganda on a Europeanist ground. Europe then became both the myth and the utopia of the neo-fascists, who abandoned previous theories of racial inequalities within the white race to share a common euro-nationalist stance after World War II, embodied in Oswald Mosley's Europe a Nation policy. The following chronology can therefore be delineated: an ideological gestation before 1919; the historical experience of fascism between 1919 and 1942, unfolded in several phases; and finally neo-fascism from 1942 onward.

Drawing inspiration from the Italian Social Republic, institutional neo-fascism took the form of the Italian Social Movement (MSI). It became one of the chief reference points for the European far-right until the late 1980s, and "the best (and only) example of a Neofascist party", in the words of political scientist Cas Mudde. At the initiative of the MSI, the European Social Movement was established in 1951 as a pan-European organization of like-minded neo-fascist groups and figures such as the Francoist Falange, Maurice Bardèche, Per Engdahl, and Oswald Mosley. Other organizations like Jeune Nation called in the late 1950s for an extra-parliamentarian insurrection against the regime in what amounts to a remnant of pre-war fascist strategies. The main driving force of neo-fascist movements was what they saw as the defense of a Western civilization from the rise of both communism and the Third World, in some cases the loss of the colonial empire.

In 1961, Bardèche redefined the nature of fascism in a book deemed influential in the European far-right at large entitled Qu'est-ce que le fascisme? (What Is Fascism?). He argued that previous fascists had essentially made two mistakes in that they focused their efforts on the methods rather than the original "idea"; and they wrongly believed that fascist society could be achieved via the nation-state as opposed to the construction of Europe. According to him, fascism could survive the 20th century in a new metapolitical guise if its theorists succeed in building inventive methods adapted to the changes of their times; the aim being the promotion of the core politico-cultural fascist project rather than vain attempts to revive doomed regimes: In addition, Bardèche wrote: "The single party, the secret police, the public displays of Caesarism, even the presence of a Führer are not necessarily attributes of fascism. ... The famous fascist methods are constantly revised and will continue to be revised. More important than the mechanism is the idea which fascism has created for itself of man and freedom. ... With another name, another face, and with nothing which betrays the projection from the past, with the form of a child we do not recognize and the head of a young Medusa, the Order of Sparta will be reborn: and paradoxically it will, without doubt, be the last bastion of Freedom and the sweetness of living."

In the spirit of Bardèche's strategy of disguise through framework change, the MSI had developed a policy of inserimento (insertion, entryism), which relied on gaining political acceptance via the cooperation with other parties within the democratic system. In the political context of the Cold War, anti-communism began to replace anti-fascism as the dominant trend in liberal democracies. In Italy, the MSI became a support group in parliament for the Christian Democratic government in the late 1950s–early 1960s, but was forced back into "political ghetto" after anti-fascist protests and violent street clashes occurred between radical leftist and far-right groups, leading to the demise of the short-lived fascist-backed Tambroni Cabinet in July 1960.

The psychologist David Pavón-Cuéllar, of the Universidad Michoacana de San Nicolás de Hidalgo, has argued that the emergence of neoliberalism in the late-twentieth century prompted neoliberalist politicians to utilize neo-fascism as a means to remove all limits to capital (including labor laws, social rights and tariffs). According to Pavón-Cuéllar, this is done by employing the aestheticization of politics and by using the narcissism of small differences to find a target for hate, maintain a social hierarchy instead of protecting all individuals.

A number of historians and political scientists have pointed out that the situations in a number of European countries in the 1980s and 1990s, in particular France, Germany and Italy, were in some significant ways analogous to the conditions in Europe in the period between World War I and World War II that gave rise to fascism in its many national guises. Constant economic crises including high unemployment, a resurgence of nationalism, an increase in ethnic conflicts, and the geo-political weakness of national regimes were all present, and while not an exact one-to-one correspondence, circumstances were similar enough to promote the beginning of neo-fascism as a new fascist movement. Because intense nationalism is almost always a part of neo-fascism, the parties which make up this movement are not pan-European, but are specific to each country they arise in; other than this, the neo-fascist parties and other groups have many ideological traits in common.

While certainly fascistic in nature, it is claimed by some that there are differences between neo-fascism and what can be called "historical fascism", or the kind of neo-fascism which came about in the immediate aftermath of World War II. Some historians claim that contemporary neo-fascist parties are not anti-democratic because they operate within their country's political system. Whether that is a significant difference between neo-fascism and historical fascism is doubted by other scholars, who point out that Hitler worked within the existing political system of the Weimar Republic to obtain power, although it took an anti-democratic but constitutional process in the form of presidential appointment rather than election through the Reichstag. Others point to the current neo-fascists not being totalitarian in nature, but the organization of their parties along the lines of the Führerprinzip would seem to indicate otherwise. Historian Stanley G. Payne claims that the differences in current circumstance to that of the interwar years, and the strengthening of democracy in European countries since the end of the war prevents a general return of historical fascism, and causes true neo-fascist groups to be small and remain on the fringe. For Payne, groups like the National Front in France are not neo-fascists in nature, but are merely "right radical parties" that will, in the course of time, moderate their positions in order to achieve electoral victory.