Skanderborg is a town in Skanderborg Municipality, Denmark. It is situated on the north and north eastern brinks of Skanderborg Lake and there are several smaller ponds and bodies of water within the city itself, like Lillesø, Sortesø, Døj Sø and the swampy boglands of Eskebæk Mose. Just north of the town on the other side of Expressway E45, is the archaeologically important Illerup Ådal. Over time, the town has grown into a suburb of Aarhus to the north east, connected by the urban areas of Stilling, Hørning and Hasselager.

Skanderborg is home to a population of 20,360 (1 January 2025), out of Skanderborg Municipality's total population of 65,760 (2025).

Skanderborg is an old town and the area have revealed traces of human settlements, dating from the earliest Nordic Stone Age. A seasonal camp from the Ertebølle culture, was found here in the 1930s for example, near the former Ringkloster (English: Ring Abbey) on the southern brinks of Skanderborg Lake.

The town sprawled around the former Skanderborg Castle, founded at some point during the early Middle Ages and in 1583 Skanderborg was granted a municipal charter.

The town of Skanderborg has attracted several religious communities over the years, especially in the early Middle Ages. The long gone Ring Abbey founded by Benedictine nuns in the 12th century, was once situated on the southeastern brinks of Skanderborg Lake. The last buildings burned down in 1715 and now there is a mansion at the site. There also used to be a Dominican monastery on the small islet of Kalvø in the middle of the lake. The monastery was founded by the Black Friar Order in the first half of the 12th century, along with a small harbour, but in 1168 there were only two monks left and the Cistercian Order took over. The Cistercians came here after they had failed in founding a proper monastery at several nearby locations since 1165. In that year, they embarked on a mission from Vitskøl Abbey in Himmerland, to found a daughter community in the diocese of Aarhus and tried at Sabro, at Sminge near Silkeborg (Sminge Abbey), and then near the village of Veng (Veng Abbey). The Cistercians eventually felt too isolated on the small isle of Kalvø, often cut off from the mainland for days and weeks even when the weather was harsh, and after just four years, they gave up here, too, and moved to Rye between Mossø and Gudensø, a few kilometres west of Skanderborg. Here they founded Øm Abbey in 1172.

The royal residence of Skanderborg Castle was arguably the most important and influential building in the history of Skanderborg, but it was demolished stone by stone during the 18th century. Founded at some point in the early Middle Ages around 1200, King Frederik II had the old medieval castle radically rebuilt and expanded around 1570. His project was grandiose in scale. An entirely new large Renaissance palace was erected and the deer park of Skanderbrog Dyrehave was constructed nearby, amongst other undertakings. Stones from the demolished Øm Abbey west of Skanderborg were used as construction materials. Many of the original structures survived the project and were incorporated into the new buildings, amongst these the old castle chapel. In the 12th-16th centuries, Skanderborg Castle functioned as the traditional hunting retreat of the Danish kings.

In the years of 1717–22, King Frederik IV began demolishing the old original medieval structures and replaced the former fortifications with terraced gardens. Only the bell tower of the still existing castle church remained. In turn however, Skanderborg Castle saw a decline in popularity and attention by the royal family, and in 1767, the castle with associated gardens was sold at auction. Commoner Hans Lauritzen bought the royal property for the sum of 3004 Rigsdaler, while the castle church with furnishings and bells was granted to the town of Skanderborg. In April 1768, the demolishing of Skanderborg Castle began and nothing remains of it today, except the old castle church.

The town of Skanderborg has a total of three churches, and Skanderborg Castle Church used to be part of the former Skanderborg Castle.