Fearmongering, or scaremongering, is the act of exploiting feelings of fear by using exaggerated rumors of impending danger, usually for personal gain.

According to evolutionary anthropology and evolutionary biology, humans have a strong impulse to pay attention to danger because awareness of dangers has been important for survival throughout their evolutionary history. The effect is amplified by cultural evolution when the news media cater to people's appetite for news about dangers.

The attention of citizens is a fiercely contested resource that news media, political campaigners, social reformers, advertisers, civil society organizations, missionaries, and cultural event makers compete over, according to attention economy.

Social agents of all kinds are often using fearmongering as a tactic in the competition for attention, as illustrated by the examples below.

Fearmongering can have strong psychological effects, which may be intended or unintended. One hypothesized effect is mean world syndrome in which people perceive the world as more dangerous than it really is. Fearmongering can make people fear the wrong things, and use too many resources to avoid rare and unlikely dangers while more probable dangers are ignored. For example, some parents have kept their children at home to prevent abduction while they paid less attention to more common dangers such as lifestyle diseases or traffic accidents. Fearmongering can produce a rally around the flag effect by increasing support for the incumbent political leaders. For example, official warnings about the risk of terrorist attacks have led to increased support for the proposed policies of US Presidents.

Collective fear is likely to produce an authoritarian mentality, desire for a strong leader, strict discipline, punitiveness, intolerance, xenophobia, and less democracy, according to regality theory. Historically, the effect has been exploited by political entrepreneurs in many countries for purposes such as increasing support for an authoritarian government, avoiding democratization, or preparing the population for war.

Daisy is a famous television commercial that aired in 1964 and was run by Lyndon B. Johnson's presidential campaign. It begins with a little girl standing in a meadow, birds chirping in the background; she picks and clumsily counts the petals off of a daisy. When she reaches 'nine', an ominous male voice begins a launch countdown. The girl's gaze turns toward the sky and the camera zooms into her eye until her pupil blackens the screen. As the countdown reaches zero, a nuclear explosion flashes on and morphs into a mushroom cloud. While the firestorm rages, Johnson's declares, "These are the stakes! To make a world in which all of God's children can live, or to go into the dark. We must either love each other, or we must die." Another voice then says, "Vote for President Johnson on November 3. The stakes are too high for you to stay home."

Fierce economic competition is driving commercial mass media to rely extensively on scary stories and bad news in a competition that has been characterized as an emotional arms race. Stories about crime, and especially violent crimes and crimes against children, figure prominently among newspaper headlines. An analysis of US newspapers has found that between 10 and 30% of headlines involve crime and fear, with a tendency to a shift of focus from isolated crime events to more thematic articles about fear. In the United Kingdom, the news media have routinely used a focus on gory sex crimes as a parameter of competition. The continued focus on emotionally touching sex crimes has had a strong influence on politics and legislation in the country.