An American musical genre which enjoyed its peak popularity between 1899 and 1918. It has had several periods of revival since then and is still being composed today.

Ragtime was the first truly American musical genre, predating jazz. It began as dance music in popular music settings years before being published as popular sheet music for piano. Being a modification of the then popular march, it was usually written in 2/4 or 4/4 time with a predominant left hand pattern of bass notes on odd-numbered beats and chords on even-numbered beats accompanying a syncopated melody in the right hand. A composition in this style is called a 'rag'. A rag written in 3/4 time is a 'ragtime waltz'.

The term 'ragtime' may actually be derived from 'ragged time'. The defining characteristic of ragtime music is a specific type of syncopation in which melodic accents occur between metrical beats. This results in a melody that seems to be avoiding some metrical beats of the accompaniment by emphasising notes that either anticipate or follow the beat. The ultimate (and intended) effect on the listener is actually to accentuate the beat, thereby inducing the listener to move to the music.

Scott Joplin, the composer/pianist known as the King of Ragtime, called the effect "weird and intoxicating". He also used the term 'swing' in describing how to play ragtime music. This name swing later came to be applied to an early genre of jazz that developed from ragtime.

The emergence of mature ragtime is usually dated to 1897, the year in which several important early rags were published. In 1899, Scott Joplin's Maple Leaf Rag was published, which became a great hit and demonstrated more depth and sophistication than earlier ragtime. Ragtime was one of the main influences on the early development of jazz (along with the blues). Some artists, like Jelly Roll Morton, performed both ragtime and jazz styles during the period the two genres overlapped.

Jazz largely surpassed ragtime in mainstream popularity in the early 1920s, although ragtime compositions continue to be written up to the present, and periodic revivals of popular interest in ragtime occurred in the 1950s and the 1970s.