Imatra is a city in Finland, located in the southeastern interior of the country. Imatra is located in the region of South Karelia, on Lake Saimaa and the River Vuoksi. The population of Imatra is approximately 25,000, while the sub-region has a population of approximately 37,000. It is the 42nd most populous municipality in Finland.

Imatra lies on the border with Russia. On the other side of the border, seven kilometres (4.3 mi) away from the centre of Imatra, lies the Russian town of Svetogorsk. The city of St. Petersburg is situated 210 km (130 mi) to the southeast, the Finnish capital Helsinki is 230 km (140 mi) away and Lappeenranta, the nearest Finnish city, is 37 km (23 mi) away.

The main employers are the pulp and paper manufacturer Stora Enso Oyj, the City of Imatra, the engineering steel manufacturer Ovako Bar Oy Ab and the Finnish Border Guard. As of October 2003^[update], the total number of employees was 12,423. As of December 2004^[update], 1,868 people were employed by the City of Imatra. The city's nicknames include Imis, Ibiza and Nahkalippis City (leather baseball cap city). Due to its location close to the border, Russian tourists are a common sight in the city, and Russian tourism is a boon to the local economy. Most people shop in Imatra, and Imatra's tax-free sales are the third largest among Finnish cities (only Helsinki and Lappeenranta are ahead).

The name of Imatra is thought to derive from a pre-Finno-Ugric language. The lightning symbols on Imatra's coat of arms refer to the power plants that were built in the early 1920s at the Tainionkoski and Imatrankoski rapids. The coat of arms was designed by Olof Eriksson [fi] and approved by the Imatra Town Council on 9 August 1950. The Ministry of the Interior approved the coat of arms for use on 25 October of the same year.

An Art Nouveau or Jugend style castle, currently known as Imatran Valtionhotelli (Imatra State Hotel), was built near the rapids in 1903 as a hotel for tourists from the Russian Imperial capital Saint Petersburg.

During the Continuation War, Carl Gustaf Emil Mannerheim met with Adolf Hitler in secrecy near the town for the former's 75th birthday.

Imatra was founded in 1948 on the territory of three municipalities – Jääski, Ruokolahti and Joutseno. Finland ceded 9% of its territory to the Soviet Union after the Winter War. Jääski lost 85% of its territory and it was decided that a new municipality, Imatra, should be established on the remaining 15% of Jääski and some areas of Ruokolahti and Joutseno. This is why the Imatra coat of arms has three flashes – in honour of those previous municipalities that granted areas to it. It gained its municipal charter in 1971.

The men's pesäpallo club Imatran Pallo-Veikot competes in the Superpesis national league, playing at Ukonniemi Stadium.