Op Art is a style of abstract painting that made use of optical illusions and other striking visual effects.

Emerging in the United States in the mid-1960s, op art generally took the form of brightly colored, tightly patterned geometric abstractions that greatly influenced fashion, commercial design, and other aspects of the popular culture of the era. The young painters who pioneered op art promoted lively, eye-catching uses of color and pattern.

Many early works of British artist Bridget Riley, for instance, involved curving parallel lines that seemed to undulate in waves across the painting's surface. Hungarian-born artist Victor Vasarely, considered one of the founders of op art, used warped geometric forms to create powerful spatial illusions, including dizzying descents into the "depths" of the painting.