WTMJ-TV (channel 4) is a television station in Milwaukee, Wisconsin, United States, affiliated with NBC. It is owned by the E. W. Scripps Company alongside Kenosha-licensed Ion Television station WPXE-TV (channel 55). WTMJ-TV's studios are located on Capitol Drive (WIS 190) in Milwaukee (an Art Deco facility that is known as "Radio City", in tribute to the New York complex of the same name), and its transmitter is located approximately four miles (6.4 km) north of downtown Milwaukee.

From its inception until October 31, 2018, WTMJ-TV was a sister station to WTMJ radio (620 AM) and WKTI (94.5 FM). The radio stations are now owned by Good Karma Brands and departed Radio City for a studio within the Third Street Market Hall in early 2022, but continue to share some operations (including a long-term weather forecasting agreement and engineering staff) with Scripps and WTMJ-TV. In January 2021, WTMJ-TV became a sister station to WPXE-TV, after Ion and its stations were purchased by Scripps; it had previously been operated by WTMJ-TV under a joint sales agreement (JSA) from 2000 to 2005.

The Journal Company (owner of the Milwaukee Journal, which was consolidated with the Milwaukee Sentinel in 1995 to become the Milwaukee Journal Sentinel) was granted its first television station license in September 1931 for W9XD. The experimental station used a low-definition electromechanical system to transmit its signal, and conducted field tests from 1931 to 1933; in 1934, Journal converted W9XD's facilities to experimental high-fidelity apex radio unit W9XAZ in 1934. Its license was withdrawn by the Federal Communications Commission (FCC) in 1938 as part of an effort to limit broadcast licenses to stations that would actively engage in the development of television. No publicly announced television programming was broadcast by W9XD during this experimental period.

The Journal Company obtained one of the first construction permits issued by the FCC for a commercial television station on December 7, 1941, under the call letters WMJT (for "Milwaukee Journal Television"), and built a new broadcast facility to transmit its signal by August 1942. However, the company's television plans were suspended when the U.S. War Production Board halted the manufacturing of television and radio broadcasting equipment for civilian use from April 1942 to August 1945, in order for such equipment to be allocated for use by the military during World War II.

The station's call sign was later modified to WTMJ-TV (referencing The Milwaukee Journal), which first signed on the air on December 3, 1947, originally broadcasting on VHF channel 3. In addition to being the first commercial television station to sign on the air in Wisconsin, the fourth such station to sign on in the Midwestern United States and the 15th to launch in the United States, WTMJ was also the first station located outside of the Eastern Time Zone to be affiliated with a major broadcast television network. At the time it began operations, there were only 500 television sets in Milwaukee; that number would jump to 2,050 by the following April. The existence of television sets in Milwaukee before WTMJ-TV even debuted was because the city is close enough to Chicago that television stations from that market could be and still are viewable in Milwaukee; therefore, residents in southeastern Wisconsin had access to WBKB-TV (now WBBM-TV), which signed on from Chicago in 1946 as the first commercially licensed television station outside of the Eastern Time Zone.

At its official sign-on, it was one of several flagship media properties owned by Journal, which in addition to the Journal newspaper, also owned radio station WTMJ (1020 AM, now on 620 AM). In 1959, these properties were joined by WTMJ-FM (now WKTI on 94.5). WTMJ-TV has been affiliated with NBC since its sign-on, owing to its radio sister's longtime affiliation with the NBC Red Network; although, it also initially carried programming from CBS, ABC and the DuMont Television Network. It lost its secondary affiliation with CBS when WCAN-TV (channel 25, now defunct) signed on in September 1953, and lost access to ABC and DuMont programming when WOKY-TV (channel 19, now CW affiliate WVTV on channel 18) made its debut one month later. WTMJ is the only television station in Milwaukee to have been affiliated with the same network throughout its history, and is currently NBC's second-longest tenured affiliate, behind only KSDK in St. Louis (which signed on as KSD-TV eleven months earlier in January 1947).

On July 11, 1953, WTMJ-TV moved to VHF channel 4, in order to alleviate interference with WKZO-TV (now WWMT) in Kalamazoo, Michigan, which is located nearly directly across Lake Michigan. The relocation of the station's channel allocation was a part of the FCC's complete revision of its Table of Channel Assignments, as issued in the Sixth Report and General Order issued by the agency on April 14, 1952. This move forced the CBS O&O on channel 4 in Chicago, WBBM-TV, to be reassigned to VHF channel 2; WBBM had moved to that frequency six days before WTMJ's channel relocation on July 5, 1953.

WTMJ-TV was one of the first television stations in the United States to purchase color equipment to transmit and produce programming in the format; in December 1953, it broadcast NBC's color telecast of Amahl and the Night Visitors, when only two prototype color sets existed in Milwaukee. The first color television sets in the city were sold in March 1954; by July of that year, WTMJ became the third television station in the U.S. with live color capability, when it broadcast its first local color program that originated from its studios, The Grenadiers. About 3,000 color sets existed in Milwaukee in February 1957.