KMEX-DT (channel 34) is a television station in Los Angeles, California, United States. It is the West Coast flagship station of the Spanish-language network Univision, owned and operated by TelevisaUnivision. Under common ownership with Ontario, California–licensed UniMás station KFTR-DT (channel 46), the two stations share studios on Center Drive (overlooking I-405) in Westchester; KMEX-DT's transmitter is located atop Mount Wilson.

KMEX was built by the Spanish International Broadcasting Company, a consortium that included American and Mexican stockholders, and began broadcasting in September 1962. It was the first full-time Spanish-language television station in the state of California and the only one in the Los Angeles area for 23 years. Its programming combined Mexican programs from Telesistema Mexicano, predecessor to Televisa, with local features relevant to the Spanish-speaking community in Los Angeles, such as courses in the English language. Spanish International Broadcasting Company grew to create the national Spanish International Network. In 1964, Danny Villanueva, then a placekicker in the NFL, began an association with the station. After retiring from football, Villanueva became KMEX's news director and later its station manager. Under Villanueva, KMEX adopted an "advocacy journalism" approach to local news and community involvement which has been adopted by much of its portion of the television industry. Ruben Salazar, a former writer for the Los Angeles Times, was working for KMEX when he was killed by riot police in August 1970; the station's retrospective coverage of the event earned it its first of two Peabody Awards.

KMEX and its co-owned stations, owned by Spanish International Communications Corporation (SICC), spent most of the 1980s embroiled in a legal dispute over the permissibility of its partially foreign ownership. In 1985, Federal Communications Commission staff recommended that all of SICC's licenses be revoked. The dispute was settled two years later by a forced sale of the stations and network to a venture of Hallmark Cards and First Chicago Ventures, which renamed the network Univision. Also in that decade, KMEX gained its first full-time competition when channel 52 was sold and switched from subscription programming to full-time Spanish as KVEA. That station's new owners, a group led by Saul Steinberg, used KVEA and other stations as the springboard to launch the competing Telemundo network in 1987. In spite of the new competition, KMEX continued to be the leading Spanish-language local TV station in news coverage and began garnering higher ratings than its English-language counterparts in key demographic groups. Its news presenters included María Elena Salinas and Jorge Ramos, both of whom went on to work for the Univision network. KMEX was the first Spanish-language TV station in the country to air an hour-long local morning show.

Univision grew from one Los Angeles–market station to two in 2002 when it acquired the USA Broadcasting group, including KFTR. In the 2010s, KMEX has had to fend off a challenge from a revitalized KVEA while expanding and refreshing its own news offerings.

There were two prior attempts to build a station on ultra high frequency (UHF) channel 34 in Los Angeles prior to KMEX-TV, in proceedings in 1954 and 1958. By 1953, the Federal Communications Commission (FCC) had received three applications for the channel, from Lawrence Harvey; Spanish International Television; and radio station KFWB (980 AM). The bid of Spanish International Television presaged that of Spanish International Broadcasting Company six years later; Emilio Azcárraga Vidaurreta was a 20 percent owner of the firm. Harvey and Spanish International Television lost interest, and their applications were dismissed in 1954, leaving the door open for KFWB. That October, however, the radio station dropped its bid; no reason was given.

Interest around the UHF allocation was revived in 1957, and in 1958, the FCC selected the application of Sherrill C. Corwin, movie theater operator from San Francisco, over a bid from Frederick Bassett and William E. Sullivan. After the FCC ordered several unbuilt UHF stations to make progress or lose their permits, Corwin proposed to sell the construction permit for what was called KMYR to Franklin James, who owned part of several regional radio stations. However, this never was completed, and the FCC deleted the KMYR permit in November 1960 (along with another Corwin held for a San Diego outlet), leaving the door open for new applications for channel 34.

On August 18, 1961, the Spanish International Broadcasting Company (SIBC) filed an application to build a new channel 34 TV station in Los Angeles. SIBC's principals reflected strong Mexican connections: Azcárraga was a 20-percent stakeholder, with the balance being held by a number of stockholders including movie theater owner Frank Fouce, the largest shareholder, and Julian Kaufman, the general manager of Tijuana's binational TV station, XETV. The FCC granted the permit on November 1, 1961, marking the first time the commission had approved an application specifying an all-foreign language TV station. From Mexico City came Rene Anselmo to manage channel 34; so too would come much of the programming, from Telesistema Mexicano.

It was also the first regular commercial UHF television station in Los Angeles. Two stations had previously operated on the band: KTHE channel 28, a short-lived educational station at the University of Southern California, and KBIC-TV channel 22, whose only telecasts to that point had been of an experimental nature. To get the Spanish-speaking community to be able to tune in, the upstart channel 34 embarked on a $100,000 public awareness campaign for UHF converters, and manufacturers stocked stores in East Los Angeles with tuning strips. While channel 34 had been set for a September 15 launch, interest in converters was so great that the station opted to broadcast the test pattern until September 30 to aid dealers installing equipment.