Spetses (Modern Greek: Σπέτσες, Katharevousa: Σπέτσαι, Spetsai, Ancient: Πιτυούσσα, "Pityoussa") is an island and a municipality in the Islands regional unit, Attica, Greece. It is sometimes included as one of the Saronic Islands. Until 1948, it was part of the old prefecture of Argolidocorinthia, which is now split into Argolis and Corinthia. In ancient times, it was known as Pityoussa, and later as Petses.
The island is now an independent municipality (pop. 4,027), with no internal boundaries within the municipality. The town of Spetses (pop. 4,001 in 2011) is the only large settlement on the island. The other settlements on the island are Moní Agíon Pánton (pop. 0), Ligonéri (4), Ágioi Anárgyroi (18), Kouzoúnos (4). Also part of the Municipality of Spetses are the islands of Spetsopoula, Falkonera, and Velopoula (all uninhabited).