The Yellow Peril is a racial color metaphor that depicts the peoples of East and Southeast Asia as an existential danger to the Western world. As a psychocultural menace from the Eastern world, fear of the Yellow Peril is racial, not national, fear derived not from concern with a specific source of danger from any one people or country, but from a vaguely ominous, existential fear of the faceless, nameless hordes of yellow people. As a form of xenophobia, Yellow Terror is the fear of the Oriental, nonwhite Other; and a racialist fantasy presented in the book The Rising Tide of Color Against White World-Supremacy (1920) by Lothrop Stoddard.

The racist ideology 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.