Right-wing terrorism, hard right terrorism, extreme right terrorism or far-right terrorism is terrorism that is motivated by a variety of different right-wing and far-right ideologies. It can be motivated by racism, ultraconservatism, ultranationalism, neo-Nazism, anti-communism, neo-fascism, ecofascism, ethnonationalism, religious nationalism, anti-immigration, anti-semitism, anti-government sentiment, patriot movements, sovereign citizen beliefs, and occasionally, it can be motivated by opposition to abortion, or homophobia. Modern right-wing terrorism largely emerged in Western Europe in the 1970s, and after the Revolutions of 1989 and the dissolution of the Soviet Union in 1991, it emerged in Eastern Europe and Russia.

Right-wing terrorists aim to overthrow governments and replace them with right-wing regimes. They believe that their actions will trigger events that will ultimately lead to the establishment of these authoritarian governments. Although they frequently take inspiration from Fascist Italy and Nazi Germany with some exceptions, right-wing terrorist groups frequently lack a rigid ideology. Right-wing terrorists tend to target people who they consider members of foreign communities, but they may also target political opponents, such as left-wing groups and individuals. The attacks which are perpetrated by right-wing terrorists are not indiscriminate attacks which are perpetrated by individuals and groups which simply seek to kill people; the targets of these attacks are carefully chosen. Because the targets of these attacks are often entire sections of communities, they are not targeted as individuals, instead, they are targeted because they are representatives of groups which are considered foreign, inferior and threatening by them.

According to an analysis by the Institute for Economics and Peace, there has been a surge in far-right terror incidents since 2010, with a 320% increase between 2014 and 2018.

German economist Armin Falk et al. wrote in a 2011 article that Right-Wing Extremist Crime (REC), which includes anti-foreigner and racist motivations, is associated with unemployment rates; as unemployment rates increase, REC also increases. A 2014 paper argues that right-wing terrorism increases with economic growth, seemingly due to its proponents often being people who lose out under economic modernisation. Conversely, a 2019 study found that economic predictors did not predict right-wing terrorism in Europe, rather, levels of extra-European immigration did; right-wing terrorists did not want immigrants in their countries and they sought to drive them out with force. Thus, increased migration caused greater resentment and thus, their greater resentment was a greater motive for their attacks.

In 2016, Thomas Greven suggested that right-wing populism is a cause of right-wing terrorism. More simply put, populism supports the advancement of "the average citizen", not the agendas of the privileged elite. Greven defines right-wing populists as those who support ethnocentrism, and oppose immigration. Because right-wing populism creates a climate of "us versus them", terrorism is more likely to occur. Vocal opposition to Islamic terrorism by Donald Trump has been obscuring right-wing terrorism in the US, where right-wing terror attacks outnumber Islamist, left-wing, and refugee attacks combined in America. Studies have also proven that radicalized alt-right male native-born attacks outnumber attacks by both documented and undocumented immigrants combined.^{[citation needed]}

In the wake of the Christchurch mosque shootings at the Al Noor Mosque and Linwood Islamic Centre in Christchurch, New Zealand, by terrorist Brenton Harrison Tarrant, expert in terrorism Greg Barton, of Deakin University in Australia (the home country of Tarrant), wrote of the "toxic political environment that allows hate to flourish". Saying that although right-wing extremism in Australia is not nearly as serious as the European neo-Nazi movements or the various types of white supremacy and toxic nationalism seen in American politics, both major parties attempted to win votes by repeating some of the tough language and inhumane policies which appeared to reward right-wing populists. He further argued: "The result has been such a cacophony of hateful rhetoric that it has been hard for those tasked with spotting the emergence of violent extremism to separate it from all the background noise of extremism".

According to Moghadam and Eubank (2006), groups which are associated with right-wing terrorism include white power skinhead gangs, far-right hooligans, and their sympathizers. The "intellectual guides" of right-wing terrorist movements espouse the view that the state must "rid itself of the foreign elements that undermine it from within" so the state can "provide for its rightful, natural citizens."

In Australia, experts, police and others have been commenting on the failure of the authorities to act effectively in order to combat right-wing radicalisation, and the government has vowed to put right-wing extremist individuals and groups under greater scrutiny and pressure, with the home affairs secretary Mike Pezzullo making strong comments to a parliamentary committee. A week after the Christchurch mosque shootings in Christchurch, New Zealand, it emerged that three years earlier, Australian-born Brenton Harrison Tarrant, the perpetrator of the shootings, had been active on the Facebook pages of two Australian-based white nationalist groups, the United Patriots Front (UPF) and True Blue Crew (TBC) and praised the UPF's leader neo-Nazi Blair Cottrell as they all celebrated Donald Trump's victory in the 2016 presidential election in the United States. Tarrant was also offered but declined a membership in the Lads Society, a white nationalist fight club which was founded by Cottrell.