Two classes of cruiser of the Royal Navy are known as the Arethusa class:

• The Arethusa class of eight light cruisers built in 1912–1914 that served in World War I.
• The Arethusa class of four light cruisers built in 1934–1936 that served in World War II.

de:Arethusa-Klasse it:Classe Arethusa ja: pl:Kr owniki typu Arethusa sv:Arethusa-klass