The Post-Impressionist School refers to a loosely affiliated group of artists working primarily in France in the late nineteenth and early twentieth centuries, whose practices evolved in response to, and often in reaction against, the innovations of Impressionism. While Impressionism had prioritised the fleeting effects of light, colour and atmosphere, Post-Impressionist painters sought to extend painting into realms of greater structure, symbolism and personal expression. The term “Post-Impressionism” was first popularised by the English critic Roger Fry in 1910 to describe artists such as Paul Cézanne, Vincent van Gogh, Paul Gauguin, and Georges Seurat. Despite their stylistic diversity, these painters shared a conviction that art should move beyond optical realism to encompass psychological depth, formal innovation and subjective vision. Cézanne emphasised underlying structure and geometry in nature, profoundly influencing Cubism and modernist abstraction. Van Gogh employed expressive colour and impassioned brushwork to convey emotion. Gauguin turned toward symbolism and the use of non-naturalistic colour, often inspired by non-Western art. Seurat developed Pointillism, a methodical approach to colour and optics that combined scientific precision with decorative order. The Post-Impressionist School was not a formal movement but rather a constellation of individual artists whose contributions collectively shaped the trajectory of modern art. Their explorations laid the foundations for later avant-garde developments, from Fauvism and Expressionism to Cubism and abstraction. Today, Post-Impressionism is recognised not only as a bridge between Impressionism and modernism but also as a defining moment when painting embraced both the materiality of form and the interiority of human experience.