音乐创作可以指一首原创乐曲、乐曲的结构或创作新音乐作品的过程。进行音乐创作的人称为作曲家。

一首乐曲必须以乐谱形式纪录其作曲，或以声音的演出（如：现场演唱或录音）存在。演出时，音乐家可以透过背谱、视谱或结合以上两者，以确实演奏事先写曲的作品。乐曲由音乐元素所组成，而元素的表现因人、因文化而异。

即兴音乐则是在演出当下作曲的一种形式，以自然天成的方式组合音乐元素。

音乐瞬间是由舒伯特创立的类似于即兴曲的曲作体裁。结构特点是短小精致，描述展现细微乐思，以及富有漫不经心的即兴性。他在1828年出版的《音乐瞬间》六首((Moment musical, Op.94))即是此类体裁的开山和代表作，皆是钢琴小品。

Musical composition can refer to an original piece of music, the structure of a musical piece, or the process of creating a new piece of music. People who practice composition are called composers. "Composition" is the act or practice of creating a song or other piece of music. In many cultures, including Western classical music, the act of composing may include the creation of music notation, such as a sheet music "score", which is then performed by the composer or other musicians. In popular music and traditional music, the act of composing, which is typically called songwriting, may involve the creation of a basic outline of the song, called the lead sheet, which sets out the melody, lyrics and chord progression. In classical music, orchestration is typically done by the composer, but in musical theatre and in pop music, songwriters may hire an arranger to do the orchestration. In some cases, a songwriter may not use notation at all, and instead compose the song mentally and then play or record it from memory. In jazz and popular music, notable recordings by influential performers are given the weight that written scores play in classical music.