Yoshino Ōishi (大石 芳野, Ōishi Yoshino, born May 28, 1944) is a Japanese photojournalist.

Ōishi was born in Suginami-ku, Tokyo on 28 May 1944. Seeing Melanesian art while at Nihon University had a big effect on her, as did a visit to Vietnam and Cambodia in 1966. After graduating in photography, she became a freelance photojournalist, working in west Africa, southeast Asia, and Europe. In 1971 she held an exhibition in the Nikon Salon of photographs of a Ghanaian child growing up in Nagano; she then spent three years photographing New Guinea. She worked on portraiture, and documented the effects of the Khmer Rouge in Cambodia, the effects of wartime dioxin in Vietnam, perestroika in the Soviet Union, and more.

Ōishi's work on Vietnam won her the Domon Ken Award. In both 1982 and 1989 she won the Annual Award from the Photographic Society of Japan. She has taught at Tokyo Polytechnic University. Her work is in the permanent collection of the Tokyo Metropolitan Museum of Photography.