Introduction
Introduction
Over the last 15 years, the nature of terrorism in the West has undergone a noticeable shift. Since the mid-2010s, most terrorist attacks in the West have been carried out by individuals who are not affiliated with a particular group, do not have a clear ideology, or who pledged allegiance to a group but did not have direct ties to any existing members.
While large-scale, highly coordinated plots carried out by recognised organisations have not vanished, fatal incidents increasingly originate from individuals acting on their own initiative, often referred to as “lone wolves”. These attackers may subscribe to a particular ideology or interact with extremist communities online, yet they do not necessarily receive formal in-person training or direct organisational resources.
Historically, lone terrorist scenarios are not new and date back to ancient times. The period between 1878 and 1934 was the era of anarchist terrorism where most actors were lone wolves because of the rejection of organised leadership. One of the earliest prominent lone wolf attacks was the assassination of US President McKinley in 1901. What distinguishes the current wave is the way in which rapid radicalisation can occur online, particularly through social media, which allows for easy access to terrorist propaganda, and the ability to self-organise and commit violent acts with minimal face-to-face contact.
Additionally, growing involvement of disaffected young people amplifies the risks of lone wolf terrorism. In some countries in the West, such as the UK, one out of every five terror suspects is under 18. Cultural alienation, easy exposure to violent propaganda and the increase in youth mental health issues, all contribute to increasing the risk of young people becoming involved in violent extremism.
In addition, minors often trigger fewer warnings within security frameworks, enjoy certain privacy protections, and, if apprehended, may be subject to less severe legal penalties. Together, these factors have produced a changing threat landscape, which requires rethinking conventional understandings of extremist violence and how best to prevent it.
Trends in Lone Wolf Terrorism
Trends in Lone Wolf Terrorism
Trends in Lone Wolf Terrorism
IEP analysis of data on terrorist attacks finds that not only is lone wolf terrorism increasing, but that lone wolf attacks are now more common than attacks carried out by groups.
Several Western nations have recorded surges in terrorism over the last decade. During 2024, the total number of terrorist incidents in the West rose to 52, up from 32 the previous year. In the overwhelming majority of these, investigators did not link the attacks to any terrorist group. As a result of this surge in terrorism, seven countries in the West are now ranked in the top 50 of the Global Terrorism Index: Germany (27th), the US (34th), France (40th), the UK (41st), Australia (46th), Canada (48th) and Sweden (50th).
IEP analysis of data on terrorist attacks finds that not only is lone wolf terrorism increasing, but that lone wolf attacks are now more common than attacks carried out by groups. Trends in Lone Wolf Terrorism IEP analysis of data on terrorist attacks finds that not only is lone wolf terrorism increasing, but that lone wolf attacks are now more common than attacks carried out by groups. The majority of fatal terrorist attacks in the West since 2017 have been lone wolf attacks.
This lone wolf data includes attackers who pledged allegiance to Islamic State shortly before the attack, despite self-radicalising independently or through radicalised sources. In some hybrid situations, external actors steered individuals towards extremist material or offered advice, but were not involved in planning or directing the attack.
This trend seems to hold true even when taking into account foiled terrorist plots, as well as attacks that were successfully carried out. For example, when looking at jihadist plots in Europe from 1994 to 2021, the number of plots by lone wolf terrorists overtook those planned by groups of two or more in 2015, and remained the dominant form of terrorism up until 2021, the last year with comparable data.
Trends in Lone Wolf Terrorism
The rise in lone wolf terrorism in the West has occurred in tandem with a rise in mass casualty shooting events. While comparable data is not available at the global level, the chart below shows the trend in mass shootings in the US between 1980 and 2024. Mass shootings are defined as single shooting incidents that result in four or more casualties.
Mass shootings in the US have been trending upwards since the turn of the century. Between 2000 and 2009 there were an average of 3.7 mass shooting events per year. From 2010 to 2019 this number rose to 5.8, and from 2020 to 2024 the average was 5.6. Although often thought of as a phenomenon unique to the US, there have been several high-profile mass shootings outside the US in the past 30 years, including the Port Arthur massacre in Australia that killed 35 people. Since 2010 there were at least ten mass shootings in Western European countries, excluding events that were classified as terrorism. The most recent event occurred in February 2025, when ten people were killed in a mass shooting in Sweden.
Mass shootings share many of the same characteristics as terrorist attacks, and given the rise in mixed or blurred ideological motivations, as well as a lack of evidence around the motivation for certain events, it is often unclear as to whether a mass shooting event should be classified as a terrorist attack. IEP analysis of data from 1980 to 2019 suggests that around 20 per cent of mass shootings in the US were classified as terrorism. However, that percentage increased over the years, and the delineation between mass shooting and terrorist attack has become more blurred over the last decade. This suggests that many of the same factors that are driving the increase in lone wolf terrorism, are also driving the increase in lone actor mass casualty attacks.
There are two other noticeable trends when looking at lone wolf terrorism since 2010: attackers are becoming progressively younger, and the timespan between initial exposure to extremist material and then planning and carrying out a terror attack has shortened considerably. By 2023, youth involvement in terrorism in the UK reached alarming levels, with a record high of 42 arrests for offenses such as disseminating terrorist propaganda and planning violent attacks. One in five terror suspects in Britain is now classified as a child. This trend has parallels elsewhere in the West. In 2024, nearly two-thirds of ISIS-linked arrests in Europe involved teenagers.
In Austria, authorities foiled a terrorist plot targeting a Vienna concert venue, arresting suspects aged 17 to 19, while in France, an 18-year-old was charged with conspiring to execute attacks during the Olympics. Australia has also grappled with youth-driven extremism, uncovering a network of teenagers planning attacks, linked to the same ideology as a 16-year-old charged with stabbing Assyrian Bishop Mar Mari Emmanuel.
As noted in one of the 2025 GTI expert essays, the average radicalisation timeline has contracted dramatically. In 2002, it took an average of 16 months from first exposure to radical material to the planning and carrying out of a terrorist attack. By 2015, this interval had decreased by over 40 per cent, primarily driven by the proliferation of online extremist content. Today, radicalisation may occur so rapidly that there might only be a few weeks between first exposure and a subsequent terrorist attack.
The Unique Threat of Lone Wolf Terrorism
The Unique Threat of Lone Wolf Terrorism
Since lone wolves can strike anywhere and may plan with minimal resources, citizens often feel that anyone could be a target.
One reason these attacks pose such a challenge is that the perpetrators seldom leave a clear intelligence footprint. Operating mostly in isolation, they do not usually communicate with large networks or rely on extensive financial backing, which limits the chances of detection. Because of their small scale and short preparation timelines, such plots often prove harder to anticipate than more elaborate plots, leading to an increased chance of an attack being successfully launched.
Lone wolf attacks can also have a disproportionate psychological effect on the public. Since lone wolves can strike anywhere and may plan with minimal resources, citizens often feel that anyone could be a target. This heightened sense of vulnerability feeds anxiety and distrust, placing additional burdens on national security and policing agencies. The involvement of minors amplifies the problem because youth suspects often do not match the typical profile of a terrorism threat. Security agencies must learn to distinguish adolescent isolation or rebellion from budding violent extremist tendencies, a task made more urgent when exposure to online propaganda can transform alienation and disaffection into lethal intent.
Characteristics and Drivers of Lone Wolf Terrorism
Characteristics and Drivers of Lone Wolf Terrorism
Youth targeting by extremist groups has emerged as a particularly unsettling trend. Technologically savvy and spending much of their time online, younger users are especially vulnerable to manipulative propaganda and extremist recruitment.
The process by which disaffected young people become radicalised can be conceptualised using the ‘bathtub model’. It likens the buildup of motivations to a bathtub being filled with water, where three different taps represent distinct categories of motivation: ideological, psychological and personal. These taps pour into the tub at varying rates, symbolising how different factors influence the individual over time. When the water level reaches the tub's capacity and overflows, it reflects the moment an individual decides to commit an attack. This model emphasises that lone wolf attacks are rarely the result of a single driving force but instead stem from a complex interplay of motivations unique to each individual.
Triggers and thresholds are key components in this model, explaining the factors that push individuals closer to action. Triggers, such as traumatic personal experiences, mental health issues, exposure to propaganda, or the desire to emulate other attackers, act as catalysts that accelerate the filling of the bathtub. Conversely, the threshold symbolises the individual's ability to contain these motivations and emotions. This threshold is dynamic, shaped by psychological stability, personal resilience, and moral or practical inhibitions. When a person’s threshold is lowered, perhaps due to mental instability, external pressures, or heightened exposure to triggers, the likelihood of the bathtub overflowing increases, making an attack more imminent.
In many such cases, the online environment accelerates radicalisation. Platforms that rely on algorithms to promote highly emotive or provocative content can reinforce harmful biases and draw vulnerable individuals deeper into violent extremism. As a result, the once-lengthy process of developing extremist views may now transpire in a matter of weeks. Simultaneously, the boundaries between political, religious and purely hate-fuelled acts are frequently blurred.
Aside from the general ease with which extremist material can be found online, there are three others key factors or triggers that can all lead to the bathtub being filled more rapidly: ideological flexibility, youth targeting by extremist groups, and the impact of ongoing geopolitical unrest.
Characteristics and Drivers of Lone Wolf Terrorism
A central feature of the recent rise in lone wolf terrorism is ideological flexibility. Lone wolves blend religious, political and conspiratorial ideas from multiple sources to create personal narratives that defy conventional labels.
A central feature of the recent rise in lone wolf terrorism is ideological flexibility. Even when attackers declare allegiance to one group, they may incorporate grievances and narratives from multiple sources, mixing religious, political and conspiratorial ideas in ways that defy conventional labels. This shape-shifting tendency is facilitated by the vast reach of digital spaces, where media producers can target content to audiences seeking identity, belonging, and purpose.
Youth targeting by extremist groups has emerged as a particularly unsettling trend. Technologically savvy and spending much of their time online, younger users are especially vulnerable to manipulative propaganda and extremist recruitment. Islamic State Khorasan Province (ISKP), for instance, has developed a multilingual media strategy that disseminates content in Pashto, Dari, Arabic, Urdu, Farsi, Uzbek, Tajik, English, Russian and Turkish. The group encourages individuals to form ‘hybrid’ plots by offering online tutorials on building improvised explosive devices, procuring firearms, or selecting targets. For intelligence and police forces, the result is a rapidly proliferating network of potential terrorists or small terrorist cells.
Finally, other factors, such as significant geopolitical events or heightened racial and religious tensions, can trigger sudden surges in radicalisation. Foreign conflicts, for instance, can fuel anti-immigrant sentiment or encourage sympathy for causes like those championed by ISIL-affiliated groups. When combined with personal challenges, mental health issues, or feelings of marginalisation, these triggers may prompt an individual to consider violent action. Given the digital sphere transcends national boundaries, extremist rhetoric spreads instantaneously, often making threats appear and evolve with very little warning.