Janša is a Slovene surname. Notable people with the surname include:
Anton Janša (1734–1773), Slovenian apiculturist and painter
Janez Janša (born in 1958 as Ivan Janša), Slovenian politician
Janez Janša (born in 1964 as Emil Hrvatin), Slovenian author, director and performer
Janez Janša (born in 1973 as Žiga Kariž), Slovenian visual artist
Janez Janša (born in 1970 as Davide Grassi), Slovenian performance artist
Leopold Jansa, Bohemian composer