Gregorio is a free and open-source scorewriter computer program especially for Gregorian chant in square notation.

[1][2][3] Gregorio is not a completely independent program, but consists mainly of three components: The gabc syntax for writing Gregorian scores, a TeX package named GregorioTeX, which is responsible for the graphical output and a converter tool between those two.

The Gregorio project started in 2006 at TELECOM Bretagne, a graduate engineering school in France.

At first, the goal of the project was just to provide the Benedictine Abbey Sainte Madeleine in Le Barroux a graphical interface for the usage of a Gregorian font.

At the end of 2006, a new developer, Olivier Berten, joined the project and created its OpusTeX component.

In following years Gregorio gained stability and popularity, strongly supported by the migration to GitHub in June 2014.

[12] The Church Music Association of America offered introductions to Gregorio on their annual conference.