Modular art is art created by joining together standardized units (modules) to form larger, more complex compositions. In some works the units can be subsequently moved, removed and added to – that is, modulated – to create a new work of art, different from the original or ensuing configurations.

Historically, alterable objects of art have existed since the Renaissance, for example, in the Triptych "The Garden of Earthly Delights" by Hieronymus Bosch or in the so-called "alterable altarpieces", such as the Isenheim Altarpiece by Matthias Grünewald, or Albrecht Dürer's Paumgartner altarpiece, where changing motifs could be revised in accord with the changing themes of the ecclesiastical calendar.

Beginning in the first half of the 20th century, a number of contemporary artists sought to incorporate kinetic techniques into their work in an attempt to overcome what they saw as the predominantly static nature of art. Alexander Calder's mobiles are among the most widely known demonstrations of physical dynamism in the visual arts, in which form has the potential to continually vary through perpetual motion, sometimes even without the agency of the human hand. Jean Tinguely's efforts to create a self-destructive art machine constitute perhaps the ultimate expression of art's mutability, in this case by taking the form of its total eradication. Victor Vasarely postulated in his Manifest Jaune in 1955 in Paris that works of art should feature the properties of being multiplicable and repeatable in series. More recently, the notion that visual art need not be conceived solely in terms of perpetually fixed objects is embodied in performance and installation art by virtue of their unfolding and temporary qualities.

Modularity enters the modern artistic repertory largely through the disciplines of industrial design and architecture. Belgian architect Louis Herman De Koninck led a team of countrymen in creating one of the first modular product systems in their Cubex kitchen series of 1932. The series consisted of standardized and industrially produced components that could be combined and arrayed in limitless combinations to accommodate almost any size kitchen. New York designer Gilbert Rohde crafted several lines of modular casework for the Herman Miller Corporation in the 1930s and 40s; like De Koninck, Rohde standardized the units in dimensions, materials and configurations to facilitate mass production and interchangeability. His Executive Office Group (EOG) line, launched in 1942, was a similarly ground-breaking systems approach to office furniture. Just a year before Eero Saarinen and Charles Eames had jointly produced a suite of modular domestic furniture for the Red Lion Company, a result of a competition held by the Museum of Modern Art in New York. In 1950 Herman Miller brought out the EAS Storage Unit series by Charles and Ray Eames, a very successful modular shelving and wall unit system that remains in production today.^{[non-primary source needed]}

The module enjoys a long history in the realm of architecture. In antiquity architects utilized the module primarily as a unit of measurement guiding the proportions of plan and elevation. The Roman author and architect Vitruvius deployed the modular method in his descriptions of the classical orders and the composition of buildings in his treatise Ten Books on Architecture, the only complete text on architecture to survive from antiquity. Architects of the Renaissance perpetuated the Vitruvian system in their resurrection of the classical orders, a tradition which continues to the present day. Among modern architects, the module is frequently employed as a design and planning tool.

Architecture and modular sculpture intersected starting in the 1950s in the work of Norman Carlberg, Erwin Hauer and Malcolm Leland. All three received commissions to design perforated architectural screens built out of repetitive modular motives cast in concrete. Non-structural, the screens were used on building exteriors to divide space, filter light and create visual interest. Their work has come to be described as modular constructivism, reflecting both its compositional methodology and its architectural context. Each created stand-alone modular-themed sculptures into the 1960s and after as well.

Robert Rauschenberg's "White Painting" of 1951 — consisting of just four equal white squares, with its geometry of interlocking forms — is among the earliest statements of modularity as an autonomous subject of art. Rauschenberg explored this theme that same year in a three- and seven-panel format; the linear array of rectangular panels in these versions suggests their potentially infinite replication. The cool abstraction of these canvases presages the emergence of modularity as a full-fledged topic of minimalist art in the 1960s. Tony Smith, Sol LeWitt, Dan Flavin and Donald Judd are among this school's most prolific exponents during the period. In particular, the work of Smith is key to understanding the transformation of modularity from a compositional and production tool into a broadly investigated artistic theme in its own right.

Smith began his career as an architectural designer. To further his education he apprenticed himself on some projects by Frank Lloyd Wright for a couple of years starting in 1938. From Wright he learned to utilize modular systems in generating architectural designs in two-dimensional plans as well as in three-dimensional applications, such as the development of building sections and interior built-ins. As an architect, Wright himself was part of a centuries-old continuum stretching back through Vitruvius to Greco-Roman antiquity in which the module was utilized to proportion built and sculpted form. In the case of Wright, the interest in modular design also may have derived from his familiarity with modular practice in traditional Japanese architecture (such as tatami).