Saint-Janvier-de-Joly (French pronunciation: [sɛ̃ ʒɑ̃vje də ʒɔli]) is a municipality in Lotbinière Regional County Municipality in Quebec, Canada.

It is part of the Chaudière-Appalaches region and had a population is 1,079 as of 2021.

It is named after Reverend Janvier Lachance, a missionary, who served the parish from 1914 to 1926.

"Joly" honours Quebec Premier Henri-Gustave Joly de Lotbinière, the owner of the seigneurie of Lotbinière, which included Saint-Janvier-de-Joly.

The post office, opened in 1924, is called Joly, name under which the municipality is most commonly known.