Tavistock was the name of a parliamentary constituency in Devon between 1330 and 1974. Until 1885 it was a parliamentary borough, consisting solely of the town of Tavistock; it returned two Members of Parliament to the House of Commons of the Parliament of the United Kingdom until 1868, when its representation was reduced to one member. From 1885, the name was transferred to a single-member county constituency covering a much larger area. (Between 1885 and 1918, the constituency had the alternative name of West Devon.)

The constituency was abolished for the February 1974 general election, when it was largely replaced by the new West Devon constituency.

1885–1918: The Municipal Boroughs of Devonport and Plymouth, and the Sessional Divisions of Hatherleigh, Holsworthy, Lifton, Midland Roborough, and Tavistock.

1918–1950: The Urban Districts of Holsworthy, Ivybridge, and Tavistock, the Rural Districts of Broadwoodwidger, Plympton St Mary, and Tavistock, and part of the Rural District of Holsworthy.

1950–1951: The Urban Districts of Holsworthy and Tavistock, the Rural Districts of Broadwoodwidger, Holsworthy, and Tavistock, and the Rural District of Plympton St Mary except the parishes of Bickleigh and Tamerton Foliot.^[1]

1951–1974: The Urban Districts of Holsworthy and Tavistock, the Rural Districts of Broadwoodwidger, Holsworthy, and Tavistock, and the Rural District of Plympton St Mary less the parts of the parishes of Bickleigh and Tamerton Foliot added to the county borough of Plymouth by the Plymouth Extension Act 1950.^[2]

In 1965 Tavistock was one of the largest seats in England, in terms of land area. It included the towns of Plympton and Plymstock (effectively eastern suburbs of Plymouth). It also included a great deal of rural land, including two-thirds of Dartmoor.^[3]