Osaka Itami Airport (大阪伊丹空港, Ōsaka Itami Kūkō; IATA: ITM, ICAO: RJOO) is the primary domestic airport for the Kansai region of Japan, including its major cities of Osaka, Kyoto, and Kobe. It is the airport closest to Osaka, being 11 km (6.8 mi) north of Osaka Station, as well as Kyoto, being 36 km (22 mi) southwest of Kyoto Station. Itami Airport has a small footprint, covering only 311 hectares (768 acres) of land.

Until January 2025, the airport was known as Osaka International Airport (大阪国際空港, Ōsaka Kokusai Kūkō), which remains the airport's official Japanese name. Despite the "international" designation, the airport caters exclusively to domestic flights. Kansai International Airport (43 km (27 mi) away) took over the region's international traffic in 1994 and competes with Itami for domestic traffic. Itami also faces competition from Kobe Airport (26 km or 16 mi away), a smaller domestic airport opened in 2006.

The airport was named after the city of Itami, Hyōgo Prefecture, because most of its land is located there. A portion of the airport property is also located in Toyonaka and Ikeda cities of Osaka Prefecture. The terminal complex is located in all three of these cities, and the only access from the Itami side is via a long tunnel that passes below the runway and apron.

In FY2006, Itami used to be Japan's third busiest airport and the Kansai region's busiest. In 2015, it had 139,450 aircraft movements, serving 14,541,936 domestic passengers and carrying 140,668 metric tons of freight cargo. In 2018, Itami was the seventh busiest in Japan, serving 16.3 million passengers. In the Kansai region, Kansai International Airport had far more passengers than Itami Airport.

Itami Airport opened as No. 2 Osaka Airport (第二大阪飛行場, Dai-ni Ōsaka Hikōjō) in 1939. Prior to the opening of Itami, Kizugawa Airport was Osaka's main civilian airport. It handled both seaplanes and conventional ones. The site of Kizugawa Airport is now a port area in Funamachi in south end of Taisho Ward with only a small marker located in Funamachi Ryokuchi Park below the Shin-Kizugawa Bridge.

In 1931, the Osaka municipal government drafted plans to construct a new "No. 1 Osaka Airport" near the mouth of the Yamato River, also targeted at seaplanes, but concerns about fog and protests from Kobe-based businesses led the government to build the "No. 2 Airport" for land-based aircraft instead.^{[unreliable source?]}

Construction began in July 1936 on a 53-hectare (131 acre) site. The new airport opened on January 17, 1939, and was primarily used by the Imperial Japanese Army during its early years. It had four runways at the time, ranging in length from 1,100 to 1,600 m, and could handle aircraft as large as the Douglas DC-3.

U.S. occupation forces took over Osaka No. 2 Airport after the end of World War II in 1945, expanding it to 221 hectares and renaming it Itami Air Base. The airfield was used extensively by US forces during the Korean War. In 1954, Marilyn Monroe and Joe DiMaggio stopped at Itami during their honeymoon, and in 1956, the base was used in the filming of the movie Sayonara. Japan Airlines operated its inaugural flight between Itami and Tokyo's Haneda Airport on October 25, 1951, using a Martin 2-0-2 aircraft leased from Northwest Airlines. JAL initially operated from a small joint-use section of the U.S. air base.