KESZ (99.9 FM) is a commercial radio station licensed to Phoenix, Arizona, featuring an adult contemporary format known as "99.9 KEZ".

KESZ's studios are located in Phoenix near Sky Harbor International Airport while the station transmitter resides in South Mountain Park.

Three applicants filed in 1976 for one of the last Class C FM allotments in Phoenix: American International Development, owned by Julia Zozaya; Herbert Owens, owner of Turf Paradise; and KXIV (1400 AM).

[5] In late 1983, Zozaya sold the station for nearly $4 million to TransCom Communications, owned by Robert G. Herpe and former KDKB owner Eric Hauenstein.

[6] By January 1984, it was apparent that a format change was likely coming as the new owners engaged former KDKB morning man Bill Andres.

[12] Success was not immediate: with the station languishing at 15th in the ratings that summer, Chase was fired and Manning moved to mornings opposite McDonald.

KESZ has continued to see success with Christmas music and is typically one of the top-rated stations in the United States during the holiday season.

[23] In September 2019, KESZ added a simulcast of KGME “Fox Sports 910” to its HD2 stream, bumping The Breeze format to HD3.