Brennilis (French pronunciation: [bʁɛnilis]; Breton: Brenniliz) is a commune in the Finistère department of Brittany in northwestern France.

The average annual rainfall is 1,508.2 mm (59.38 in) with January as the wettest month.

The temperatures are highest on average in July, at around 16.7 °C (62.1 °F), and lowest in February, at around 5.3 °C (41.5 °F).

Inhabitants of Brennilis are called Brennilisiens in French.

This Finistère geographical article is a stub.