KZZO (100.5 MHz "Now 100.5") is a commercial FM radio station licensed to Sacramento, California. It broadcasts an Adult Top 40 radio format and is owned by Salt Lake City–based Bonneville International, a profit-making subsidiary of the Church of Jesus Christ of Latter-day Saints. KZZO's studios and offices are on Commerce Circle in Sacramento near the American River and the North Sacramento Freeway (California State Route 160). KZZO is one of four stations operated by Bonneville in the Sacramento radio market, along with FM stations KNCI and KYMX plus AM station KHTK.

KZZO has an effective radiated power (ERP) of 115,000 watts, grandfathered at an unusually high power. The transmitter is on Alder Creek Parkway in Folsom, near U.S. Route 50. KZZO broadcasts in the HD Radio hybrid format, with its HD2 digital subchannel carrying an Dance/EDM format. The station carries the Brooke & Jeffrey morning drive time show, syndicated by Premiere Networks from KQMV Seattle.

The station signed on the air in October 1958 as KEBR, a Christian radio station owned by Family Radio, an Oakland based organization. After a three decades of broadcasting religious music and bible talks from radio evangelist Harold Camping, Family Radio sold 100.5 to commercial owners in 1988, with Family Radio eventually relocating to KEBR (1210 AM) in Rocklin, (now South Asian station KRPU), and FM 88.1, which now carries the KEBR call letters.

The new owners installed a Smooth Jazz format on April 16, 1988, re-branded it as The Point and changed its call sign to KQPT. Over a seven-year period, The Point went through a couple of ownership changes and format tweaks (mostly towards album rock).

Brown Broadcasting changed the branding to "The Zone" in September 1995 and the format to a wide-ranging AAA mix it promoted as "bands you've never heard of." Brown sold KQPT, KXOA (AM) and KXOA-FM to American Radio Systems in 1996. The call letters were switched to KZZO in 1997. There was a three-way battle for rock listeners during this period between KWOD, KRXQ (93 Rock) and "The Zone."

However, after a year as a AAA, KZZO began evolving to Hot Adult Contemporary, later moving to Modern Adult Contemporary (after the shift of KGBY to Hot Adult Contemporary in 2007).

KZZO remained in that format until June 22, 2010, when it shifted to a broader Adult Top 40 direction and adopted the "Now" approach. KZZO was the first Adult Top 40 station in the CBS Radio stable to use the slogan, as "Now" is more associated with a Rhythmic pop-leaning Top 40/CHR brand; unlike other "Now" stations, KZZO, due being an Adult Top 40 and having Rhythmic Top 40 KSFM as a sister station (at the time), will not play any hip hop songs, although it does share some artists (i.e. Kesha and Lady Gaga) at both stations. In addition, KZZO has vowed not to play any gold or recurrent songs from the 80s or 90s, a message aimed directly at rival KGBY, whose playlist featured a more conventional hot AC approach. Later that year, the “Now” branding was brought onto WPBZ in West Palm Beach, Florida, a hot AC station owned by CBS Radio (this station would later flip to Sports, as WAXY-FM was sold by CBS and relocated into the Miami market). After Entercom divested KZZO, the slogan dropped the "Without the Rap" tagline.

By December 2011, KZZO became the only hot adult contemporary radio station in Sacramento due to Clear Channel changing KGBY to news-talk as KFBK-FM, simulcasting KFBK. However, the following week, KZZO no gained a competitor in KBZC, which flipped from rhythmic adult contemporary to hot AC; the competition would last until February 2017, when the station (now known as KUDL) flipped to Top 40, leaving KZZO as Sacramento's only hot AC station again.