Eibar (Basque: Eibar, Spanish: Éibar) is a city and municipality within the province of Gipuzkoa, in the Autonomous Community of Euskadi. It is the capital of the eskualde / comarca of Debabarrena.

Eibar has 27,138 inhabitants (Eustat, 2018). Its chief industry is metal manufacturing, and the city has been known since the 16th century for the manufacture of armaments, particularly finely engraved small arms. It was also the home of Serveta scooters.

It is home to the SD Eibar football team.

Eibar lies at an altitude of 121m above sea level, in the west of the province of Gipuzkoa, very close to Biscay. Eibar has an oceanic climate. The town lies in a narrow valley in a mountainous area, with mountains like Karakate, Kalamua and Akondia being between 700 and 800 metres tall. Eibar is traversed by the river Ego, which is a tributary of the Deba.

Apart from the urban area, the municipality consists of five rural neighbourhoods: Otaola-Kinarraga, Aginaga, Arrate, Mandiola and Gorosta.

The city was chartered by Alfonso XI of Castile in 1346, receiving the name of Villanueva de San Andrés de Heybar.

The feudal families that dominated the territory engaged in the War of the Bands. Eibar, like the rest of settlements in the valley, had an industry based on finery forges and arms manufacturing. In 1766, Eibar was engaged in a social revolt known as the Machinada, and years later, in 1794, it was attacked by the French, who destroyed the town.

In the 19th century, industrialisation transformed the systems of production in the city and spawned a powerful social movement. After the rest of Gipuzkoa sided with the French in 1793 during the French Revolutionary Wars, Eibar temporarily voted to join Biscay. In the Carlist Wars, Eibar sided with the Liberals. The labour movement and socialism became particularly strong in Eibar. In 1931, it was the first city in Spain to proclaim the Second Spanish Republic; in recognition it was given the title of "Very Exemplary City".