Johannes Ludwig Janson (1 September 1849 – 28 October 1914) was a German specialist in veterinary science.

He is noted for having introduced western veterinary science to Meiji period Japan in the late 19th century.

[1] Janson was hired by the Meiji government of Japan as a foreign advisor and arrived in Tokyo in October 1880.

Janson's contract was extended several times, and he continued teaching at Komaba 1902.

Janson wrote a number of scientific papers on the domestic animals and veterinary medicine practices in Japan Janson married a Japanese woman, and his grave is in Kagoshima, the native place of his wife.