Flight display screens at Vietnam's two largest airports were hacked to show messages criticising Vietnam's claims of territory in the South China Sea.
China's territorial claims, which overlap with Vietnam's, were recently rejected by an international tribunal.
Screens and sound systems at Hanoi and Ho Chi Minh City airports broadcast anti-Vietnamese and Philippines slogans on Friday.
Vietnam's transport ministry said a Chinese hacker was responsible.
Vietnam Airlines' website was also briefly hacked.
Media in Vietnam reported that staff at the airports had to resort to checking in passengers manually, avoiding computers for several hours.
The hack comes days after a row involving a Chinese tourist at one of the hacked airports - Tan Son Nhat, in Ho Chi Minh City.
China asked Vietnam to investigate reports that a Chinese visitor's passport was handed back with obscenities written on two pages.