KOSY (790 AM) was a radio station broadcasting an oldies format. Licensed to Texarkana, Arkansas, United States, it served the Texarkana area. The station was owned by Townsquare Media. Studios were located on Arkansas Boulevard in Texarkana, Arkansas, with a transmitter site on Line Ferry Road in the south portion of the city. The Line Ferry Road site had two towers, constructed for a nighttime directional signal of 500 watts, that later operated non-directional on one tower with 23 watts at night.

The radio station was originally built in 1951 by W. Decker Smith, MD, as an investment. It was affiliated with the CBS Radio Network. His son, James K. Smith, ran the station for many years as the general manager. The studios were established in the same building at 119 E. 6th as the Smith Clinic medical practice. Well into the 1980s, until the building was destroyed by a fire, remnants of the old medical practice remained on the upper floors including X-ray equipment and examination tables (the broadcasting studios were on the lower floors).

In 1989, the younger Smith, who had suffered a heart attack and was approaching retirement, sold the station to corporate interests along with its sister station, KOSY-FM (Y102), which was broadcasting a contemporary hit format at the time of sale. The new owners changed the call signs to KKYR and implemented a country music format, which exists to this day. The transmitter site of KOSY remains on the city's southern border off Line Ferry Road but KKYR began transmitting from a taller shared tower near Robinson Road in Texarkana shortly after the sale. This new broadcast tower could properly accommodate the 100,000-watt Class C license held by Smith since the station's sign-on in 1965 (the station operated at only 35,000 watts for many years).

On December 30, 2021, KOSY changed its format from gospel to oldies, branded as "Good Time Oldies 790/107.5", launching on FM translator K298DB, licensed to Texarkana, using the Good Time Oldies format from Westwood One. The station requested authority to go silent on October 4, 2022. The licenses for KOSY and K298DB were later surrendered on March 30, 2023, and cancelled on March 31, 2023.

• Good Time Oldies 790/107.5
• Facility details for Facility ID 7072 (KOSY) in the FCC Licensing and Management System
• FCC History Cards for KOSY (covering 1949-1981)