Ploudalmézeau (French pronunciation: [pludalmezo]; Breton: Gwitalmeze) is a commune in the Finistère department of Brittany in north-western France.

The average annual rainfall is 1,006.4 mm (39.62 in) with November as the wettest month.

The temperatures are highest on average in August, at around 17.0 °C (62.6 °F), and lowest in January, at around 7.7 °C (45.9 °F).

In 2008, 11.69% of primary-school children attended bilingual schools, where Breton language is taught alongside French.

[6] On 16 March 1978, Amoco Cadiz, a very large crude carrier (VLCC), owned by Amoco, split in three after running aground on Portsall Rocks, 5 km (3.1 mi) from the coast of Portsall, resulting in the largest oil spill of its kind in history to that date.