Guadeloupe is an archipelago of more than 12 islands, as well as islets and rocks situated where the northeastern Caribbean Sea meets the western Atlantic Ocean. It is located in the Leeward Islands in the northern part of the Lesser Antilles, a partly volcanic island arc. To the north lie Antigua and Barbuda and the British Overseas Territory of Montserrat, with Dominica lying to the south.

The two main islands are Basse-Terre (west) and Grande-Terre (east), which form a butterfly shape as viewed from above, the two 'wings' of which are separated by the Grand Cul-de-Sac Marin, Rivière Salée and Petit Cul-de-Sac Marin. More than half of Guadeloupe's land surface consists of the 847.8 km² Basse-Terre. The island is mountainous, containing such peaks as Mount Sans Toucher (4,442 feet; 1,354 metres) and Grande Découverte (4,143 feet; 1,263 metres), culminating in the active volcano La Grande Soufrière, the highest mountain peak in the Lesser Antilles with an elevation of 1,467 metres (4,813 ft). In contrast Grande-Terre is mostly flat, with rocky coasts to the north, irregular hills at the centre, mangrove at the southwest, and white sand beaches sheltered by coral reefs along the southern shore. This is where the main tourist resorts are found.

Marie-Galante is the third-largest island, followed by La Désirade, a north-east slanted limestone plateau, the highest point of which is 275 metres (902 ft). To the south lies the Îles de Petite-Terre, which are two islands (Terre de Haut and Terre de Bas) totalling 2 km².

Les Saintes is an archipelago of eight islands of which two, Terre-de-Bas and Terre-de-Haut are inhabited. The landscape is similar to that of Basse-Terre, with volcanic hills and irregular shoreline with deep bays.

There are numerous other smaller islands, most notably Tête à l'Anglais, Îlet à Kahouanne, Îlet à Fajou, Îlet Macou, Îlet aux Foux, Îlets de Carénage, La Biche, Îlet Crabière, Îlets à Goyaves, Îlet à Cochons, Îlet à Boissard, Îlet à Chasse and Îlet du Gosier.