From 3 to 17 March 1967, "Leary" briefly served as a Sonar School Ship at Key West, Florida. On 5 July "Leary" once again passed through the Panama Canal and was quickly en route to an extended tour of duty off the coast of Vietnam. She was accompanied by the destroyers , , and . On arrival, she was immediately assigned to provide needed gunfire support off the Vietnamese coast as she alternated duty with the carriers on Yankee Station. Periodically, "Leary" reinforced the 7th Fleet cruisers and she provided naval gunfire support to allied forces in South Vietnam. On 9 October "Leary" operated on Baie de Ganh Rai of the Mekong River Delta in South Vietnam.