Neo-Nazism comprises the post–World War II militant, social, and political movements that seek to revive and reinstate Nazi ideology. Neo-Nazis employ their ideology to promote hatred and racial supremacy (often white supremacy), attack racial and ethnic minorities (often antisemitism and Islamophobia), and in some cases to create a fascist state.

Neo-Nazism is a global phenomenon, with organized representation in many countries and international networks. It borrows elements from Nazi doctrine, including antisemitism, ultranationalism, racism, xenophobia, ableism, homophobia, anti-communism, and creating a "Fourth Reich". Holocaust denial is common in neo-Nazi circles.

Neo-Nazis regularly display Nazi symbols and express admiration for Adolf Hitler and other Nazi leaders. In some European and Latin American countries, laws prohibit the expression of pro-Nazi, racist, antisemitic, or homophobic views. Many Nazi-related symbols are banned in European countries (especially Germany) in an effort to curtail neo-Nazism.