The island of Lastovo is an island municipality in the Dubrovnik-Neretva County in Croatia. The municipality consists of 46 islands with a total population of 835 people, and a land area of approximately 53 km2 (20 sq mi). The biggest island in the municipality is also named Lastovo, as is the largest town. The majority of the population lives on the 46 km2 island of Lastovo. Lastovo has a dynamic landscape consisting of 46 hills and 46 karstic fields that often contain layers of red soil and quartz sand. The highest point is Hum at 417 m (1,368 ft) and there are another three hills higher than 400 m (1300 ft), Pleševo Brdo, Gumanca and Mali Hum and another thirteen other hills higher than 200 m (650 ft). Its dolomitic valleys are located between limy hills and mild calcareous slopes rich in caves. There are five caves on the island — Rača (the largest), Puzavica, Pozalica, Grapčeva and Medvidina.

The coastline is mainly steep and the surrounding sea is deep. On the southern coast is a large, deep bay at Skrivena Luka which offers protection from the bura and westerly winds. The other main deep port is located on the western side at Ubli which is where the main ferry port for the island is located. The western coast of Lastovo and the eastern coast of the islet of Prezba enclose a number of picturesque coves, well protected from the bora: Velo Jezero in the south and Malo Jezero in the north.

The island is noted for its 15th- and 16th-century architecture. There is a large number of churches of relatively small size, a testament to the island's long-standing Roman Catholic tradition. The major cultural event is the Poklade, or carnival. The most important event on the island is an authentic carnival that the locals call the Poklad. All the island residents participate by wearing folk costumes. The origins of the Lastovo carnival go back to a historical event. Legend has it that Catalan pirates attacked neighbouring Korčula and sent a Turkish messenger to Lastovo to tell the islanders to surrender or they would be next. The inhabitants of Lastovo did not let themselves be intimidated — instead they armed themselves and went on the attack. The women and children prayed to Sv. Jure (St. George) for help and their prayers were answered: a storm destroyed the pirates' ships and the inhabitants of Lastovo caught the messenger. In order to mock him, he was taken through the village on the back of a donkey and was afterwards sentenced and burned to death. This event is celebrated through the Poklad every year over a period of three days. The event takes place in the middle of February and since the summer 2006 it has become main attraction for tourists. Locals enjoy this event very much and Lastovci from all around Croatia return to Lastovo to attend the carnival.The island largely relies on its natural beauty and preservation to attract tourists each season. In 2006 the Croatian Government made the island and its archipelago a nature park.