Alphonse Matejka (9 January 1902 – 27 October 1999) was a Swiss exports specialist and proponent of international auxiliary language.

Born in St. Gallen to a Czech father and Swiss mother, he worked in the textiles and watchmaking industries, and lived much of his life in La Chaux-de-Fonds.

[2][1] After the death of Bellanger in 1987, Matejka withdrew from public activities and moved to the nursing home L'Escale (English: The Stopover) in La Chaux-de-Fonds; he died on 27 October 1999, aged 97.

[2] Matejka took on roles in several societies, and attended four congresses; for the next three years, he was a member of the Ido club in St. Gallen, and later joined an organisation for the language in Paris.

[8] And years later, a thunderstorm broke out, although only a very small portion of the world population noticed it, when the Idist Alphonse Matejka... switched to de Wahl's army.

[9][11] Author of several courses and textbooks for Interlingue, for over two decades[a] between 1937 and 1985, Matejka was editor of Cosmoglotta, the main organ of the Occidental movement.

[11] When Interlingua was published by the IALA in 1951, many Occidentalists left Interlingue,[b] especially following Berger's departure – this largely destroyed the movement.

[9][14] Matejka found the two languages to be 90% similar in vocabulary, and the Interlingue-Union advocated positive relations with the Interlingua movement, even after the IALA was liquidated in 1953.