It's What's Happenin' (subtitled The Varitone Sound of Clark Terry) is an album by American jazz trumpeter Clark Terry featuring performances recorded in 1967 for the Impulse! label. Remastered in 2012 to commemorate the 50th anniversary of Impulse! Records, it was reissued together with Terry's only other record for the label as a solo leader, The Happy Horns of Clark Terry.