Landivisiau (; ) is a commune in the Finistère department of Brittany in north-western France. The journalist Luc Le Vaillant, winner of the 1998 Albert Londres Prize was born in Landivisiau. Landivisiau is twinned with Bideford in north Devon.
Landivisiau has an oceanic climate (Köppen climate classification Cfb). The average annual temperature in Landivisiau is . The average annual rainfall is with December as the wettest month. The temperatures are highest on average in August, at around , and lowest in January and February, at around . The highest temperature ever recorded in Landivisiau was on 18 July 2022; the coldest temperature ever recorded was on 13 January 1987.
Landivisiau is home to the . A squadron of 25àAir-Sol Moyenne Portée nuclear armed Rafale M from the French Navy is based at Landivisiau.
It is twinned with Bideford in the southwest of the United Kingdom and Bad Sooden-Allendorf in Hesse, Germany.
Inhabitants of Landivisiau are called in French Landivisiens.
In 2008, 7.11% of primary-school children attended bilingual schools, where Breton language is taught alongside French.