Csepel Island (Hungarian: Csepel-sziget) is the largest island of the River Danube in Hungary. It is 48 km long; its width is 6–8 km. Its area comprises 257 km². The word Csepel is pronounced CHE-pel.

Csepel Island extends south from Budapest; its northern point is Csepel, which is Budapest's District XXI. Most of the island is accessible from Budapest by the suburban railway.

Notable towns include Ráckeve, Szigetszentmiklós, Szigethalom and Tököl.

Csepel island was the first centre of conquering Hungarians, being the lodgement of Árpád's tribe. The island is named after Árpád's horse groom, Csepel.

Coordinates: 47°15′N 18°57′E / 47.25°N 18.95°E / 47.25; 18.95

Csepel (German: Tschepele) is the 21st district and a neighbourhood in Budapest, Hungary. Csepel officially became part of Budapest on 1 January 1950.

Csepel is located at the northern end of Csepel Island in the Danube, and covers one tenth of the island's area. Being on an island, it is the only complete district of Budapest which is neither in Pest nor in Buda. It has approximately 85,000 inhabitants.

Csepel is most easily accessed from central Budapest by the Csepel HÉV. Bridges connect Csepel to southern parts of Pest, Ferencváros and Pesterzsébet, and a ferry links Csepel to Soroksár.

The village and the island was named after the first comes (ispán) of the area, Csepel. The German and Serbo-Croatian names derived from the older Hungarian one.