Gagra (Georgian: გაგრა; Russian and Abkhaz: Гагра) is a town in Abkhazia/Georgia, sprawling for 5 km on the northeast coast of the Black Sea, at the foot of the Caucasus Mountains. Its subtropical climate made Gagra a popular health resort in Imperial Russian and Soviet times.

It had a population of 26,636 in 1989, but this has declined considerably as a result of ethnic cleansing of Georgians in Abkhazia and other demographic shifts during and after the War in Abkhazia (1992–93).

Gagra is the center of the district of the same name. It is located in the western part of the region of Abkhazia, and the Psou River serves as the border with the Krasnodar Krai of Russia.

According to a number of Georgian scholars, Gagra is derived from Gakra meaning "walnut" in the Svan language, while Gakari/Kakari means "a place with walnut trees", which is in accordance to toponym used in old maps. The name of the city is claimed by Z. Danelia to originate from the Gagaa family, who, according to Danelia, once lived there. However, the historicity of the Gagaa family and its connection to the city is disputed due to lack of evidence. According to V. Kvarchia, the name Gagra is derived from a combination of two Abkhaz words: a-ga ("coast") and a-kra ("to close"), that is, "a place where the shore is closed". According to Z. Anchabadze, etymology of the city is derived from "Gagrifshi." The term "Gak" or "Kak" is considered a personal name, while the affix "-ri" denotes possession. Additionally, the affix "-fsh-" is interpreted as indicating "the importance of the place."

The town was established as a Greek colony in the kingdom of Colchis, called Triglite (Ancient Greek: Τριγλίτη), inhabited by Greeks and Colchians. Colchis came under the control of the kingdom of Pontus in the 1st century BC before being absorbed by the Roman Empire, which renamed the town as Nitica. Its geographical position led the Romans to fortify the town, which was repeatedly attacked by Goths and other invaders. The town and the whole region of Colchis remained part of Byzantine Empire.

It became a major trading settlement in which Genoese and Venetian merchants were prominent, trading in the town's main exports – wood, honey, wax and slaves. The name "Gagra" appeared for the first time on a map in 1308, on a map of the Caucasus made by the Italian Pietro Visconti, which is now in the Library of Saint Mark in Venice.

In the 16th century, Gagra and the rest of western Georgia were conquered by the Ottoman Empire. The western merchants were expelled and the town entered a prolonged period of decline, with much of the local population fleeing into the mountains. By the 18th century, the town had been reduced to little more than a village surrounded by forests and disease-ridden swamps. Its fortunes were restored in the 19th century when the Russian Empire expanded into the region, annexing the whole of Georgia. The swamps were drained and the town was rebuilt around a new military hospital. Its population, however, was still small; in 1866, a census recorded that 336 men and 280 women, mostly local families or army officers and their dependents, lived in Gagra. The town suffered badly in the Russo-Turkish War, 1877-1878, when Turkish troops invaded, destroyed the town and expelled the local population. Russia won the war, however, and rebuilt Gagra again.

In 1904 the town was discovered by Duke Alexander of Oldenburg, a member of the Russian royalty. He saw the potential of the region's sub-tropical climate and decided to build a high-class resort there. Having raised a large sum of money from the government, he built a palace there for himself and constructed a number of other buildings in an eclectic variety of architectural styles from around Europe. A park was laid out with tropical trees, and parrots and monkeys were imported to give it an exotic feel. Despite the expensive work, the resort was not initially a success, although it did later attract a growing number of foreign tourists visiting on cruises of the Black Sea. Following the founding of the resort, the area was ceded from Sukhum Okrug to Black Sea Governorate in 1904.