The Yellow Peril (also the Yellow Terror and the Yellow Specter) is a racist color metaphor that depicts the peoples of East and Southeast Asia as an existential danger to the Western world.

The concept of the Yellow Peril derives from a "core imagery of apes, lesser men, primitives, children, madmen, and beings who possessed special powers", which developed during the 19th century as Western imperialist expansion adduced East Asians as the Yellow Peril. In the late 19th century, the Russian sociologist Jacques Novikow coined the term in the essay "Le Péril Jaune" ("The Yellow Peril", 1897), which Kaiser Wilhelm II (r. 1888–1918) used to encourage the European empires to invade, conquer, and colonize China. To that end, using the Yellow Peril ideology, the Kaiser portrayed the Japanese and the Asian victory against the Russians in the Russo-Japanese War (1904–1905) as an Asian racial threat to white Western Europe, and also exposes China and Japan as in alliance to conquer, subjugate, and enslave the Western world.

The sinologist Wing-Fai Leung explained the origins of the term and the racialist ideology: "The phrase yellow peril (sometimes yellow terror or yellow specter) ... blends Western anxieties about sex, racist fears of the alien Other, and the Spenglerian belief that the West will become outnumbered and enslaved by the East." The academic Gina Marchetti identified the psycho-cultural fear of East Asians as "rooted in medieval fears of Genghis Khan and the Mongol invasions of Europe [1236–1291], the Yellow Peril combines racist terror of alien cultures, sexual anxieties, and the belief that the West will be overpowered and enveloped, by the irresistible, dark, occult forces of the East";^: 2 hence, to oppose Japanese imperial militarism, the West expanded the Yellow Peril ideology to include the Japanese people. Moreover, in the late-19th and early-20th centuries, writers developed the Yellow Peril literary topos into codified, racialist motifs of narration, especially in stories and novels of ethnic conflict in the genres of invasion literature, adventure fiction, and science fiction.

Whilst this barbarianism applied to Asian men in particular (East and Southeast Asian men), conversely, the same did not apply to Asian women (East and Southeast Asian women), where Asian women were often subjected to fetishism, seen as ideal women to be bred for white men, in the vein of yellow fever instead. Asian men were subjected to nasty racial stereotypes and were seen as undesirable whilst Asian women were seen as being able to be assimilated to white or Western society.