Arenzano (local Ligurian: Rensën) is a coastal town and comune in the Metropolitan City of Genoa, Liguria, northern Italy, facing the Ligurian Sea.

The town is home to many of the employees of the nearby architectural firm of Renzo Piano.

Part of the municipality territory, which is mountainous by grossly two thirds, is within the boundaries of the Parco naturale regionale del Beigua.

[3] The vast majority of the town's territory extends in the mountain range of the Beigua Regional Park with peaks above 1000 m above sea level.

The ancient toponym of the municipality, Arentianis, would go back to a property or possession of the Arentii Ligurian family.