Op art is a style of painting from the 20th century that became known during the years 1963-1966. The term is an abbreviation of the English term optical art. Op art works with different optical illusions.

The method in this art movement originated from the geometric abstract art and is sometimes related to the kinetic art of the same period, which however is rather a movement in sculpture. Op art is a very accessible art form; less experienced art viewers are being directly addressed to it. The artists of the op art, included their paintings with strong contrasts, vibrating colors, moiré patterns and compositions that seem to move while watching.

By responding to the movement and behavior of the observer, op art is a very advanced interactive art form. The observer and the artwork together make the definitive perception. Because of this basic feature, the art contrasts with classical painting. Op art is often presented in the context of ZERO and kinetic art.

The basis for the op-art was laid by the Polish-French painter Henryk Berlewi who, together with El Lissitzky and Kasimir Malevich was part of the Suprematist Proun group. He created the theory of his Mechano-Faktura in Berlin between 1922 and 1924. He created a forum for a number of French abstract artists who experimented with optical phenomena, which they used to create non-narrative, non-perspectival compositions, shortly before World War II. With geometric planes, transparent color layers and overlaps they created impressions of vibration, pulsating light, and other spontaneous optical sensations.

After the liberation of Paris in 1944, the gallery Denise René was founded. Soon a number of artists grouped around the Hungarian painter Victor Vasarely. He became the most famous of all op art artist.

However, the term op art was only first mentioned in October 1964 in Time Magazine and was only fully defined by R. H. Carraher and J. Thurston in their study Optical Illusions and the Visual Arts, in 1966. The art criticst therefore relied on the theoretical work Interaction of colors, from 1963, by Professor Josef Albers.

From about 1963, op art boomed. Many of these artists took part in 1965 in the exhibition The Responsive Eye at the Museum of Modern Art in New York City. After this exhibition, a large international responce interest for op art developped, that even penetrated into the world of fashion

Elements of op art found parallels in the psychedelic art, kinetic art, in the hard-edge and minimal art.