Feodosia (Ukrainian: Феодосія, Теодосія, Feodosiia, Teodosiia; Russian: Феодосия, tr. Feodosiya), also called in English Theodosia (from Greek: Θεοδοσία), is a city on the Crimean coast of the Black Sea. Feodosia serves as the administrative center of Feodosia Municipality, one of the regions into which Crimea is divided. During much of its history, the city was a significant settlement known as Caffa (Ligurian: Cafà) or Kaffa (Old Crimean Tatar/Ottoman Turkish: کفه‎; Crimean Tatar/Turkish: Kefe). According to the 2014 census, its population was 69,145.

The city was founded as Theodosia (Θεοδοσία) by Greek colonists from Miletos in the 6th century BC. Noted for its rich agricultural lands, on which its trade depended, the city was destroyed by the Huns in the 4th century AD.

Theodosia remained a minor village for much of the next nine hundred years. It was at times part of the sphere of influence of the Khazars (excavations have revealed Khazar artifacts dating back to the 9th century) and of the Byzantine Empire.

Like the rest of Crimea, this place (village) fell under the domination of the Kipchaks and was conquered by the Mongols in the 1230s.

A settlement named Kaphâs (alternate romanized spelling Cafâs, Greek: Καφᾶς) existed surrounding Theodosia prior to the penetration of Genoese into the Black Sea. The archaeological evidence indicates that during the Middle Ages the population about Theodosia never decreased to zero; several medieval churches are found in the area dating from the times of Late Antiquity/Early Middle Ages. However, the population had become completely agrarian. A small local Greek population must have existed in situ and in the neighboring settlements. Likely, from the 9th century there were Cumans and Goths living alongside the Greeks, and by 1270s, perhaps some Tatars and Armenians as well.

In the late 13th century, traders from the Republic of Genoa arrived and purchased the city from the ruling Golden Horde.

They established a flourishing trading settlement called Kaffa (also recorded as Caffa), which virtually monopolized trade in the Black Sea region and served as a major port and administrative center for the Genoese settlements around the Sea. The city thrived despite the tenuous politics of the region and Genoa's series of wars with the Mongol successor states.

It came to house one of Europe's biggest slave markets of the Black Sea slave trade, and served as a terminus for the Silk Road. The Great Soviet Encyclopedia also adds that the city of Caffa was established during the times when the area was ruled by the Khan of the Golden Horde Mengu-Timur.