Western swing is a subgenre of American country music that originated in the late 1920s in the Southwestern U.S. 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 40s until a federal war-time nightclub tax in 1944 led to its decline.

The movement was an outgrowth of jazz, and similarities with Gypsy jazz are often noted. The music is an amalgamation of rural, cowboy, polka, folk, 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 the fully orchestrated bands—vocals and other instruments followed the fiddle's lead. Additionally, although popular horn bands tended to arrange and score their music, most Western bands improvised freely, either by soloists or collectively.

Prominent groups during the peak of Western swing's popularity included The Light Crust Doughboys, Bob Wills and The Texas Playboys, Milton Brown and His Musical Brownies, and Spade Cooley and His Orchestra. Current groups include Asleep at the Wheel and The Hot Club of Cowtown.

According to legendary guitarist 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."