KLCS (channel 58) is a tertiary PBS member television station in Los Angeles, California, United States. Owned by the Los Angeles Unified School District (LAUSD), it is one of eight television stations in the U.S. that are operated by a local school system. KLCS' studios are located at the former Downtown Magnets High School campus on West Temple Street in downtown Los Angeles, and its transmitter is located atop Mount Wilson.

KLCS is one of four PBS member stations in the Los Angeles market; the others are KVCR-DT (channel 24) in San Bernardino, which serves the Inland Empire; KOCE-TV (channel 50) in Huntington Beach; and KOCE-TV's sister station KCET (channel 28) in Los Angeles, which KOCE-TV replaced in 2011 as the city's primary PBS station. Since the spectrum auction in 2018, when KLCS sold its physical channel, it has been a guest on KCET's channel 28 signal. KLCS remains the fifth most-watched public television station in the country.

In October 1957, the Los Angeles Unified School District began producing televised instructional programs to be viewed in school by students. By the 1966–67 school year, it was producing over 700 television programs per year for broadcast on various local stations in the Los Angeles area and leasing airtime to broadcast 40 hours of instructional programming Monday through Friday each week. Over the years, the district earned the support of teachers and administrators who were impressed with the effectiveness of the programs on the learning experience in the classroom.

In 1963, the LAUSD began the application process to acquire a license from the Federal Communications Commission (FCC) and launch its own full-service television station on UHF channel 58. In 1967, the district also applied for and later received state and federal grants to build and equip a broadcast facility for the new station. In the summer of that year, advocates for the LAUSD testified before the FCC on the benefits of an instructional television station for students, staff and the local community. Five years later, on March 3, 1972, the FCC granted the district a license to broadcast on channel 58, and the new station signed on the air on November 5, 1973, as KLCS, the call letters an apparent acronym for "Los Angeles City Schools".

The station presently produces more than 700 hours of educational, informational, sports and entertainment programming a year, including live telecourse instruction from the California State University system. It is one of five television stations licensed in the Los Angeles market that continue to utilize their original call signs, alongside KTLA (channel 5), KTTV (channel 11), KCET (channel 28) and KMEX-TV (channel 34).

Since 1984, KLCS has produced Homework Hotline. Created by then general manager Patricia Prescott-Marshall, Homework Hotline is a weekday afterschool call-in program where students receive homework help from LAUSD teachers and other faculty who appear on the show. In its first year, Homework Hotline was featured in a Time magazine article titled "Education: Help from the Hotline", and has won many Los Angeles Area Emmy Awards over the years, including two in 1986 for Best Instructional Program and Creative Technical Crafts.

Unlike most public television stations, KLCS does not hold an annual pledge drive. However, its website lists special premiums and discounts given to subscribers who support the station at various levels, including recognition on-air and in KLCS' monthly viewer magazine. KLCS was slated to begin high definition broadcasting in the autumn of 2014, but remained in standard definition until April 23, 2018, when the station began HD broadcasting at 720p following a reallocation to digital channel 28.

For a period of time, instead of broadcasting a 24-hour program schedule, KLCS signed off at the end of each broadcast day, ceasing programming on some or all of its four subchannels at either 1 or 2 a.m. and resuming its schedule later that morning at either 5 or 6 a.m. One subchannel may continue overnight programming, such as for Create programs or regular meetings of the Los Angeles County Board of Supervisors, while the others have individually signed off. In lieu of a test pattern, an overnight-themed title card is aired reminding viewers to tune in again when programming resumes. This made KLCS one of the largest television stations in the United States by market size to still have traditional sign-on and sign-off procedures. KLCS has since resumed a 24-hour schedule. Its second digital subchannel also broadcasts 24 hours a day and is featured as part of DirecTV's digital programming package.