KXII (channel 12) is a television station licensed to Sherman, Texas, United States, serving the Sherman, Texas–Ada, Oklahoma market as an affiliate of CBS, MyNetworkTV, and Fox. It is owned by Gray Media alongside low-power Telemundo affiliate KAQI-LD (channel 28). The two stations share studios on Texoma Parkway (SH 91) in northeastern Sherman, with an additional studio on South Commerce Street (US 77) and Elks Boulevard in southwestern Ardmore, Oklahoma. KXII's transmitter is located along US 377 in rural northeastern Marshall County, Oklahoma (southwest of Madill).

KXII's signal is relayed on low-power translator station KXIP-LD (channel 12) in Paris, Texas (in the Dallas–Fort Worth television market), and also on the second and third subchannels of KAQI-LD.

The station first signed on the air as KVSO-TV, on August 12, 1956. Originally licensed to Ardmore, Oklahoma, it was founded by a family-led consortium led by Albert Riesen, Maurine Easley and their children, John and Buddy Riesen, and Betty Dillard. The Riesen-Easley family had assumed ownership of The Daily Ardmoreite and KVSO (1240 AM) from Maurine's father, John Easley—longtime owner of the newspaper/radio station combination, who had acquired the Ardmoreite in 1917—following his retirement the year prior.

After the family filed an application with the Federal Communications Commission (FCC) for the construction permit in 1954, the Reisen-Easleys obtained VHF channel 12 for their proposed television station after negotiating with Eastern Oklahoma Television, Inc., owner of Ada-based competitor KTEN (channel 10), for the allocation (the FCC had reassigned the channel 12 allocation to the Sherman–Ada market following the issuance of the Sixth Report and Order in 1952, in which the agency moved the same assignment from Waco to Abilene, Texas, where it would become occupied by present-day ABC affiliate KTXS-TV, to avoid interference with the Sherman-Ada frequency).

Channel 12 originally operated as an NBC affiliate; however the Riesen-Easley ownership group was unable to afford the expenditures to acquire a feed to access NBC's television programming directly; this forced station engineers to have to switch to and from the broadcast signal of NBC affiliate WKY-TV (now KFOR-TV) in Oklahoma City, whenever WKY aired programming from the network. In addition, KVSO-TV carried some of WKY's local and syndicated programming intermittently within its broadcast day. The station originally maintained transmitter facilities from a tower located north of Ardmore in the Arbuckle Mountains, on a site that also formerly housed the transmitter of KVSO-FM.

On April 2, 1957, the station's 360 feet (110 m) transmission tower was felled by a strong tornado (later retroactively rated as an F2) that touched down west of Dougherty and hit portions of northern Carter County, Oklahoma. Transmitter engineer Chester Rollins was near the tower at the time the tornado hit and escaped serious injury, despite the transmission building he was in losing its roof. The tower fell onto a pickup truck, which was shifted 75 yards (69 m), killing the male driver. The station set up temporary transmission facilities near its Ardmore studio, where its signal originated until the following year, when a new transmitter and tower was constructed near Madill (about 25 miles (40 km) southeast of Ardmore), in order to provide better reception to viewers in Durant and across the Red River to the Sherman–Denison, Texas area.

In late 1958, the Riesen family sold KVSO-TV to Texoma Broadcasting, a holding company owned by businessman Milford N. "Buddy" Bostick, who founded fellow CBS affiliate KWTX-TV in Waco, Texas three years earlier (The Daily Ardmoreite remained under the Riesens' ownership until 1983, when they sold the newspaper to Stauffer Communications). Shortly after the sale's closure, the station changed its call letters to KXII (signifying the Roman numeral for 12).

In the spring of 1960, channel 12 began maintaining a secondary affiliation with CBS. At that time, in addition to carrying the majority of NBC's programming lineup, CBS fare cleared to air on KVSO for most of the 1960s consisted mainly of daytime programs and sporting events (such as National Football League [NFL] game telecasts, including those involving the Dallas Cowboys). In 1960, the station opened a secondary studio facility located along U.S. Highway 75, halfway between Sherman and Denison (the building would later become the station's main studios in 1974). During the 1960s and early 1970s, most CBS programming was fed to cable subscribers in the Texoma area via the network's affiliates in surrounding markets, including KWTV in Oklahoma City, KAUZ-TV in Wichita Falls, and KRLD-TV (now Fox owned-and-operated station KDFW) in Dallas–Fort Worth. KXII's direct competitor, KTEN, was a primary ABC affiliate at the time but also carried select programming from NBC (mainly running programs that KXII did not give clearance to air) through a secondary affiliation.