A gospel harmony is an attempt to compile the canonical gospels of the Christian New Testament into a single account. This may take the form either of a single, merged narrative, or a tabular format with one column for each gospel, technically known as a synopsis, although the word harmony is often used for both.

Harmonies are constructed for a variety of purposes: to create a readable and accessible piece of literature for the general public, to establish a scholarly chronology of events in the life of Jesus as depicted in the canonical gospels, or to better understand how the accounts relate to each other.

Among academics, the construction of harmonies has been favoured by conservative scholars, though one scholar, B. S. Childs, opposes this. Students of higher criticism see the divergences between the gospel accounts as reflecting the construction of traditions by the early Christian communities. Among modern academics, attempts to construct a single story have largely been abandoned in favour of laying out the accounts in parallel columns for comparison, to allow critical study of the differences between them.

The earliest known harmony is the Diatessaron by Tatian in the 2nd century and variations based on the Diatessaron continued to appear in the Middle Ages. The 16th century witnessed a major increase in the introduction of gospel harmonies and the parallel column structure became widespread. At this time visual representations also started appearing, depicting the life of Christ in terms of a "pictorial gospel harmony", and the trend continued into the 19th–20th centuries.

A gospel harmony is an attempt to collate the Christian canonical gospels into a single account. Harmonies are constructed by some writers in order to make the gospel story available to a wider audience, both religious and secular. Harmonies can be studied by scholars to establish a coherent chronology of the events depicted in the four canonical gospels in the life of Jesus, to better understand how the accounts relate to each other, and to critically evaluate their differences.

The terms harmony and synopsis have been used to refer to several different approaches to consolidating the canonical gospels. Technically, a "harmony" weaves together sections of scripture into a single narrative, merging the four gospels. There are four main types of harmony: radical, synthetic, sequential and parallel. By contrast, a "synopsis", much like a parallel harmony, juxtaposes similar texts or accounts in parallel format, synchronized by time, while preserving their individual identity, usually in columns. Harmonies may also take a visual form and be undertaken to create narratives for artistic purposes, as in the creation of picture compositions depicting the life of Christ.

The oldest approach to harmonizing consists of merging the stories into a single narrative, producing a text longer than any individual gospel. This creates the most straightforward and detailed account, and one that is likely to be most accessible to non-academic users, such as lay churchgoers or people who are reading the gospels as a work of literature or philosophy.

There are, however, difficulties in the creation of a consolidated narrative. As John Barton points out, it is impossible to construct a single account from the four gospels without changing at least some parts of the individual accounts.