Svendborg (Danish: [ˈsvenˌpɒˀ] ^ⓘ) is a town on the island of Funen in south-central Denmark, and the seat of Svendborg Municipality. With a population of 27,616 (1 January 2025), Svendborg is Funen's second largest city. In 2000 Svendborg was declared "Town of the year" in Denmark, and in 2003 it celebrated its 750th anniversary as a market town. By road, Svendborg is located 195 kilometres (121 mi) southwest of Copenhagen, 183 kilometres (114 mi) south of Aarhus, 44.2 kilometres (27.5 mi) south of Odense, and 28.5 kilometres (17.7 mi) east of Faaborg.

Svendborg is home to "Danmarks Forsorgsmuseum" social history museum and "Naturama" natural history museum. The latter holds a wide variety of taxidermy from whales and bears to birds and Foxes.

The largest container ship company in the world, A.P. Møller-Mærsk has its origins in Svendborg, in the "Villa Anna".

In the light of archaeological discoveries, Svendborg appears to have been established in the first half of the 12th century or even earlier. Located at the head of a bay, the natural harbour encouraged seafaring and trade.

The first recorded mention of Svendborg occurred in 1229 in a deed of gift by Valdemar the Victorious, where he refers to the fortification as Swinæburgh. The name is thought to consist of the elements "svin" meaning "pig" and "borg" meaning "fortification". In 1236, the Greyfriars monastery in Svendborg was established. The Greyfriars would be part of the city for the next 300 years, until the Protestant reformation in 1536. The ruins of the monastery were partly excavated beside the railway in 2007.

In 1253, the city was granted market town privileges by King Christopher I. In the Middle Ages, the city was fortified with walls and moats. The defense system also included a few of forts. Most historical facts about the medieval defense system, including the locations of fortifications, are disputed, as little archaeological evidence has been generated. In spite of this, it is a popular theory that the three towers in the coat of arms are the three fortifications ("Skattertårnet", "Kyseborg" and a third one unnamed). Thanks to its seafarers, in the late Middle Ages Svendborg became one of the most important trading centres in Scandinavia.

During the time of the Protestant reformation and the Count's Feud in the 1530s, the citizens of Svendborg joined forces with the King. Ørkild Castle, located just east of Svendborg, was property of the bishop of Odense, who was less than popular among the citizens of the city. The tension resulted in the castle being seized and burned down by an angry mob in collaboration with the King's forces. The King's forces would later, after ending their north-going campaign on Funen, return to pillage and plunder Svendborg.

After 1536, Svendborg went through a brief period of progress becoming the islands main port. But it would not last for long. In the following 250 years, the city faced various setbacks in its development, such as plague, a major fire, and the effects of the Swedish wars when Svendborg's ships were destroyed.