Free improvisation or free music is improvised music without any general rules, instead following the intuition of its performers. The term can refer to both a technique—employed by any musician in any genre—and as a recognizable genre of experimental music in its own right.

Free improvisation, as a genre of music, developed primarily in the U.K. as well as the U.S. and Europe in the mid to late 1960s, largely as an outgrowth of free jazz and contemporary classical music. Exponents of free improvised music include saxophonists Evan Parker, Anthony Braxton, Peter Brötzmann, and John Zorn, composer Pauline Oliveros, trombonist George E. Lewis, guitarists Derek Bailey, Henry Kaiser and Fred Frith, bassists Damon Smith and Jair-Rohm Parker Wells and the improvising groups Spontaneous Music Ensemble and AMM.