Rhodes is the largest of the Dodecanese islands of Greece and is also the island group's historical capital. Administratively the island forms a separate municipality within the Rhodes regional unit, which is part of the South Aegean administrative region. The principal town of the island and seat of the municipality is Rhodes. The city of Rhodes had 50,636 inhabitants in 2011. It is located northeast of Crete, southeast of Athens. Rhodes' nickname is The Island of the Knights, named after the Knights of Saint John of Jerusalem, who ruled the island from 1310 to 1522.

Historically, Rhodes island was very famous worldwide for the Colossus of Rhodes, one of the Seven Wonders of the Ancient World. The Medieval Old Town of the City of Rhodes has been declared a World Heritage Site. Today, it is one of the most popular tourist destinations in Europe. The name of the U.S. state of Rhode Island is thought to be based on this island.

The island of Rhodes is shaped like a spearhead, 79.7 km (49.5 mi) long and 38 km (24 mi) wide, with a total area of approximately 1,400 square kilometres (541 sq mi) and a coastline of approximately 220 km (137 mi). Limestone is the main bedrock. The city of Rhodes is located at the northern tip of the island, as well as the site of the ancient and modern commercial harbours. The main airport is the (Diagoras International Airport, IATA code: RHO) is located 14 km (9 mi) to the southwest of the city in Paradisi. The road network radiates from the city along the east and west coasts.

Outside the city of Rhodes, the island is dotted with small villages of white-wash homes and spa resorts, among them Faliraki, Lindos, Kremasti, Haraki, Pefkos, Archangelos, Afantou, Ixia, Koskinou, Embona (Attavyros), Paradisi, and Trianta (Ialysos). There are mineral-rich spring water (and sometimes sea water) used to give medicinal baths and the spa resorts offer various health treatments.

Rhodes is situated 363 km (226 mi) east-southeast from the Greek mainland, and 18 km (11 mi) from the southern shore of Turkey.