Arganil (Portuguese pronunciation: [ɐɾɣɐˈniɫ]) is a municipality in Coimbra District in Portugal. The population in 2011 was 12,145, in an area of 332.84 km².
The present mayor is Ricardo João Pereira Alves, elected by the Social Democratic Party. The municipal holiday is September 7.
Administratively, the municipality is divided into 14 civil parishes (freguesias):
- Cepos e Teixeira
- Cerdeira e Moura da Serra
- Coja e Barril de Alva
- Pombeiro da Beira
- São Martinho da Cortiça
- Vila Cova de Alva e Anseriz