“International Exhibition, Tsukuba Japan 1985” was held in Tsukuba Science City, Ibaraki Prefecture, Japan, from March 17 to September 16, 1985. Organized by the Japan Association for the International Exposition, Tsukuba, 1985, it was a specialized exhibition under the theme "Dwellings and surroundings - Science and Technology for Man at Home." Over 184 days, it recorded 20,334,727 visits.

The idea dates from 1978, when Japan's Ministry of International Trade and Industry proposed an Expo on how science and technology could shape the future. Tsukuba was chosen for its concentration of research centers and the facilities of Tsukuba Science City. The General Assembly of the International Exhibitions Bureau (Bureau International des Expositions, BIE) approved the theme in April 1981, and ground was broken in 1982, about 30 months before opening. Organizers wanted visitors to learn through participation and hands-on experience.

According to Japan's Ministry of Foreign Affairs, 48 countries, including Japan, and 37 international organizations took part, and the Britannica International Encyclopedia notes that 28 Japanese companies and groups also exhibited. The Soviet Union presented technology for energy, housing, education and culture; the United Kingdom focused on efforts toward "a better and healthier world for all"; France showed models of urban landscapes, suburban redevelopment, and a home designed for people with disabilities; and the United States explored artificial intelligence with an exhibit on "Robots that think." Many developing countries also took part, encouraging the exchange of new technologies.

Japanese pavilions explored the theme from several angles. The Theme Pavilion was divided into "My Land," on nature and Japan's resources, and "My Life," on humanity's place in nature, while the History Pavilion traced the arrival and growth of Western science in Japan. At the Tsukuba Expo Centre, the Cosmic Hall presented what the BIE describes as the first HDTV system, and the Science Forum answered questions in 16 languages. Corporate pavilions such as the Fuyo Robot Theatre, the Suntory Pavilion, and the Mitsubishi Future Pavilion drew large crowds; the Mitsubishi monorail was later reused at Expo 1988 Brisbane. In the Children's Plaza, the "Fun Tube" led young visitors through wind, rain, fog and echoes.

With more than 20 million visits, Expo 1985 Tsukuba ranks among the most visited specialized exhibitions. It strengthened the infrastructure of Tsukuba Science City and linked it to the Joban Expressway, and the city today hosts about 60 public and 240 private research institutions. The Tsukuba Expo Center continues as a hands-on science museum with a large planetarium, operated by the Tsukuba Science Expo Memorial Foundation. Expo 1985 Tsukuba presented Japan's commitment to advanced technology to audiences at home and abroad.