Devon County Council is the county council administering the English county of Devon. The council is based at Devon County Hall in the city of Exeter.

The area administered by the county council is termed the non-metropolitan county, which is smaller than the ceremonial county; the non-metropolitan county excludes Plymouth and Torbay. The population of the non-metropolitan county was estimated at 795,286 in 2018, making it the most populous local authority in South West England.

Devon is an area with "two-tier" local government, meaning that the county is divided into non-metropolitan districts carrying out less strategic functions, such as taking most planning decisions. There are eight such districts in the county council's area, each with its own district, borough, or city council.

Devon County Council was established in 1889 under the Local Government Act 1888, which created elected county councils to take over the administrative functions previously performed by unelected magistrates at the quarter sessions. Three boroughs within the geographical county of Devon were excluded from the county council's authority: Devonport, Exeter, and Plymouth, which were each considered large enough for their existing councils to take on county-level functions. They were therefore made county boroughs. The county council was elected by and provided services to the remainder of Devon outside those three boroughs, an area termed the administrative county.

The first county council elections were held on 16 January 1889, and the council formally came into being on 1 April 1889. On that day it held its first official meeting in the courthouse at Rougemont Castle (also known as Exeter Castle), which had been the meeting place of the quarter sessions which preceded the county council. Charles Hepburn-Stuart-Forbes-Trefusis, 20th Baron Clinton, a Conservative peer, was the first chairman of the council. He had been the chairman of the Devon quarter sessions since 1863 and was also the Lord Lieutenant of Devon.

The council's budget in its first year was £50,000 (equivalent to £5,560,000 in 2025). In 1907, women became eligible for election and the first female councillor was elected in 1931.

Stonehouse was removed from the administrative county in 1914 when it and Devonport were absorbed into the county borough of Plymouth. Torbay was created as a new county borough in 1968, removing it from the administrative county.

In 1971, Devon County Council signed a twinning charter with the Conseil General of Calvados to develop links with the French department of Calvados.