Western swing is a subgenre of American country music that originated in the late 1920s in the West and South among the region's Western string bands. It is dance music, often with an up-tempo beat, which attracted huge crowds to dance halls and clubs in Texas, Oklahoma and California during the 1930s and 1940s until a federal war-time nightclub tax in 1944 contributed to the genre's decline.

The movement was an outgrowth of jazz. The music is an amalgamation of rural, cowboy, polka, old-time, Dixieland jazz, and blues blended with swing; and played by a hot string band often augmented with drums, saxophones, pianos and, notably, the steel guitar. The electrically amplified stringed instruments, especially the steel guitar, give the music a distinctive sound. Later incarnations have also included overtones of bebop.

Western swing differs in several ways from the music played by the nationally popular horn-driven big swing bands of the same era. In Western bands, even fully orchestrated bands, vocals, and other instruments followed the fiddle's lead, though like popular horn-led bands that arranged and scored their music, most Western bands improvised freely, either by soloists or collectively.

According to country singer Merle Travis, "Western swing is nothing more than a group of talented country boys, unschooled in music, but playing the music they feel, beating a solid two-four rhythm to the harmonies that buzz around their brains. When it escapes in all its musical glory, my friend, you have Western swing."