Borgholm (Swedish: [ˈbɔ̂rjhɔlm]) is a city and the seat of Borgholm Municipality, Kalmar County, Sweden with 4,401 inhabitants in 2020. It is located on the island of Öland in the Baltic Sea, at the Kalmar Strait-side of Öland, north of Färjestaden.

Borgholm is one of Sweden's historical towns with a former city status (stad). The city is best known for its once-magnificent fortress – Borgholm Castle – which is now in ruins. Borgholm is, despite its small population, for historical reasons normally still referred to as a city. Statistics Sweden, however, only counts localities with more than 10,000 inhabitants as cities.

Borgholm is the main city of Öland, but remains one of the smallest cities in Sweden.

The city is situated some 20 kilometres (12 miles) north of the Öland Bridge, which connects the island with the city of Kalmar on the mainland.

The name Borgholm is documented to be found from the 1280s. The foreland Borg- is considered to refer to the old ancient castle which is believed to have been located on the site of the castle ruins, but according to another interpretation refers to the eye-catching topography of the site. The significance would then be that berg- is the correct interpretation, and support for this can be found in Gotlandic, where borg can mean beach hill or high sand dune, and that berg-meaning has been well spread throughout the East Nordic area.

During the Viking Age, there was a marketplace in Köpingsvik dating from the 8th century.

The oldest evidence refers to the medieval castle, which was on the site. The oldest evidence is a letter issued by King Magnus Birgersson at the castle. Borgholm's castle was located in Borg parish, whose parish church was located next to the castle, and the oldest preserved parts date from the beginning of the 12th century. Borgholm's then castle was destroyed in connection with Sören Norby's siege of the castle in 1520 after which Borgholm was transformed into a royal court.

The city received its charter in 1816 and emerged as a spa-town in the shadow of the ruins of the once mighty Borgholm Castle, which burned down in 1806. So important and magnificent was this castle, that it has become the city arms, and the ruins are the best known attraction in the municipality, perhaps on the entire island of Öland. Slightly further south is Halltorps Estate, a historic royal estate linked to Borgholm Castle. Borg parish was most recently dissolved at the beginning of Gustav Vasa's government and merged with Räpplinge. The church was blown up in connection with the Kalmar War. Borgholm, however, continued to function as a fishing village and port for crossings between Öland and the mainland, the port has previously been called Borghamn.