Italo-Byzantine is a style term in art history, mostly used for medieval paintings produced in Italy under heavy influence from Byzantine art. It initially covers religious paintings copying or imitating the standard Byzantine icon types, but painted by artists without a training in Byzantine techniques. These are versions of Byzantine icons, most of the Madonna and Child, but also of other subjects; essentially they introduced the relatively small portable painting with a frame to Western Europe. Very often they are on a gold ground. It was the dominant style in Italian painting until the end of the 13th century, when Cimabue and Giotto began to take Italian, or at least Florentine, painting into new territory. But the style continued until the 15th century and beyond in some areas and contexts.

Maniera greca ("Greek style/manner") was the Italian term used at the time, and by Vasari and others; it is one of the first post-classical European terms for style in art. Vasari was no admirer, defining the Renaissance as a rejection of "that clumsy Greek style" ("quella greca goffa maniera"); other Renaissance writers were similarly critical.

This also covered actual Byzantine icons in Italy; by the Renaissance these were imported on a large scale from Crete, then a Venetian possession. Especially in later periods, the terms also cover paintings done in Italy by Greek or Greek-trained artists; some of these are difficult to distinguish from works of the Cretan School, the main source of Greek imports to Europe. In the mid-20th century, many of these were attributed to Venetian Dalmatia, which is now less popular among scholars.

According to John Steer, "down to the thirteenth century ... all Italian local schools [of painting] were provincial variants of the central Byzantine tradition". Most of the artists of Italo-Byzantine paintings are unknown, though we know some facts about later transitional figures such as Coppo di Marcovaldo in Florence (active mid-13th century), and Berlinghiero of Lucca (active c. 1228–42). The gold ground style encouraged strong outlines in the painted shapes, and "figures are formed out of abstract but expressive shapes designed to identify various body parts or items of clothing while creating beautiful patterns."

The term "Italo-Byzantine" is used for sculpture much less often, as the Byzantines did not provide large models to follow for that. It may be used of ivories, mosaics and the like. In architecture it is the almost inevitable term used for San Marco, Venice, and a few other very old buildings in Venice (the Fondaco dei Turchi for example) and on the small islands of Torcello (Torcello Cathedral) and Murano in the lagoon, but is not often used for other buildings (until 19th-century revivals such as Westminster Cathedral and Bristol Byzantine). Even the rest of Venetian Gothic architecture does not owe much to Byzantium.

The people of the parts of southern Italy and Sicily ruled by the Byzantines during the High Middle Ages often continued to speak Greek until about the 16th century and had Greek Orthodox religious habits. They and things relating to them may be called Italo-Byzantine, or alternatively "Italo-Greek" or "Italo-Albanian". The Eastern Catholic Italo-Byzantine or Italo-Albanian Catholic Church was set up to enable them to keep Orthodox traditions within the Catholic Church; it now has some 70,000 members, not all in Italy.

Variants of maniera greca in contemporary sources such as inventories included alla greca, more greco, grechescha and pittura greca, as well as ones using "Cretan" or "Candia", the Venetian name for Heraklion, then as now the main city on Crete. These included quadro a la candiota and quadro candiota piccolo ("a small Candia picture"); they are probably best regarded as a characterization by style rather than a record of the place of origin. Especially for Venetian paintings, modern art history may use local terms such as scuola veneto-bizantina ("Venetian-Byzantine school") or "Byzantine (Greco-Venetian) School", especially in Italian.

Maniera greca had a different meaning from the 17th century, when it described a trend in Baroque sculpture especially associated with Francois Duquesnoy, a Flemish sculptor working in Rome and his pupils such as Rombaut Pauwels. Duquesnoy's Saint Susanna (1633) in Santa Maria di Loreto, Rome is an example. At the time even artists in Rome were able to see very little actual ancient Greek sculpture, and their idea of "Greekness" is rather subtle and hard to reconstruct today; to a large degree it relates to Hellenistic sculpture rather than that of earlier periods, and gives a more restrained and less dramatic style of Baroque than that of, say, Bernini.