MuseScore is a free music notation and composition software available for Windows, Mac, and Linux.

Rosegarden is a well-rounded audio and MIDI sequencer, score editor, and general-purpose music composition and editing environment.

Sibelius is a scorewriter program, created by Sibelius Software (now part of Avid Technology) for Microsoft Windows, OS X, and historically RISC OS.

Band-in-a-Box is an intelligent automatic accompaniment program. You can hear and play along to many song ideas and go from "nothing" to "something" in a very short period of time with Band-in-a-Box as your "on demand" backup band.

Flat lets you write sheet music with your friends in real time with a nice music notation editor.

GNU LilyPond is a computer program for music engraving. One of LilyPonds major goals is to produce scores that are engraved with traditional layout rules, reflecting the era when scores were engraved by hand.

GNU Denemo is a music notation editor that lets you rapidly enter notation for typesetting via the LilyPond music engraver. You can compose, transcribe, arrange, listen to the music and much more.

StaffPad is a brand new class of notation app, designed to take advantage of the advanced pen and touch input found on Microsoft Surface* and other compatible Windows 8.1 devices. As you write notation using the pen, StaffPad recognises your handwritten music and converts it...

DaCapo Editor is a free Open Source music sheet editor which allows to easily create nice looking partitions. It is available as a web application as well as a desktop application for Windows, MacOS and Linux.

MC Musiceditor is free/open source (GPLv2) music notation software (Windows). It has been developed with only one purpose: to make life of musicians easier when making scores. This results in a userfriendly editor which makes professional scores without requiring specific...

Music21 is a Python-based toolkit for computer-aided musicology. Applications of this toolkit include computational musicology, music informations, musical example extraction and generation, music notation editing and scripting, and a wide variety of approaches to composition, bo.

Busker is a complete set of tools to create musical arrangements from sheet music (chords + melody staff). It uses Yamaha compatible styles (thousands can be downloaded for free) for auto-accompaniment.