Pan-Asianism (also known as Asianism or Greater Asianism) is an ideology aimed at creating a political and economic unity among Asian peoples. Various theories and movements of Pan-Asianism have been proposed, particularly from East, South and Southeast Asia. The motive for the movement was in opposition to the values of Western imperialism and colonialism, and that Asian values were superior to European values.

The concept of Asianism in Japan and China has changed during the early 20th century from a foreign-imposed and negatively received, to a self-referential and embraced concept, according to historian Torsten Weber.

The concept of a unified Asia under Japanese leadership had its roots dating back to the 16th century. For example, Toyotomi Hideyoshi proposed to make China, Korea, and Japan into "one". Moreover, Hideyoshi had further planned to expand into India, the Philippines, and other islands in the Pacific.

Originally, Japanese Pan-Asianism believed that Asians shared a common heritage and must therefore collaborate in defeating their Western colonial masters. However, Japanese Asianism mostly focused on East Asian territories, with occasional references to South East Asia and West Asia.

The first lasting pan-Asianist organisation started in Japan. In 1877, inspired by Ōkubo Toshimichi's promise to Chinese statesman Li Hongzhang to promote Chinese-language schools in Japan as a channel of mutual understanding, a Pan-Asianist body was established in Japan known as Shin'akai (Promoting Asia Society), followed by the more successful Kōakai (Raising Asia Society) in 1880. Both focused on the promotion of mutual understanding through providing language education, setting up schools in Japan for teaching Chinese and Korean languages, as well as branches in Korean and Chinese cities. China's envoys to Japan and Korean reformers held membership, and even two diplomats from the Ottoman Empire. The Society used Classical Chinese as the common language of East Asian Pan-Asianists. Japanese Pan-Asianism before 1895 was characterized by an egalitarian view on relations between China, Korea and Japan; in order to avoid the accusation that Japan sought to 'lead' Asia, the Kōakai changed its name to the "Asia Association."

Pan-Asianist ideologues included Tokichi Tarui (1850–1922) who argued for equal Japan-Korea unionization for cooperative defence against the European powers, and Kentaro Oi (1843–1922) who attempted to push social reforms in Korea and establish a constitutional government in Japan.^{[citation needed]} Pan-Asian thought in Japan was further popularized following the defeat of Russia in the Russo-Japanese War (1904–1905). This sparked interest from Indian poets Rabindranath Tagore and Sri Aurobindo and Chinese politician Sun Yat-sen.^{[citation needed]}

The growing official interest in broader Asian concerns was shown in the establishment of facilities for Indian Studies. In 1899, Tokyo Imperial University set up a chair in Sanskrit and Kawi, with a further chair in comparative religion being set up in 1903. In this environment, a number of Indian students came to Japan in the early twentieth century, founding the Oriental Youngmen's Association in 1900. Their anti-British political activity caused consternation to the Indian Government, following a report in the London Spectator.

Okakura Kakuzō, a scholar and art critic, also praised the superiority of Asian values upon Japanese victory of the Russo-Japanese War: