KZST (100.1 FM) is a commercial radio station licensed to Santa Rosa, California, and serving Sonoma County.

"[6] Founded by Gordon Zlot, KZST was long-time operated under the ownership of his company, Redwood Empire Stereocasters.

Jim Grady, the weekend morning host, held that distinction until March 26, 2004, when he was released from news/talk station KSRO after 44 years.

KZST for a number of years aired two syndicated radio shows hosted by Dick Clark, Rock, Roll, and Remember was on Saturday nights, and Countdown America was on Sunday mornings.

In June 2022, it was announced that KZST and sister stations KWVF, K256DA, and K273CU would be sold by Redwood Empire Stereocasters to Amaturo Sonoma Media Group for $6 million.