Penryn and Falmouth was the name of a constituency in Cornwall, England, UK, represented in the House of Commons of the Parliament of the United Kingdom from 1832 until 1950. From 1832 to 1918 it was a parliamentary borough, initially returning two Members of Parliament (MPs), elected by the bloc vote system.

Under the Redistribution of Seats Act 1885, its representation was reduced to one member, elected by the first past the post system. In 1918 the borough was abolished and the name was transferred to a county constituency electing one MP.

1918–1950: The Municipal Boroughs of Falmouth, Penryn, and Truro, the Urban District of St Austell, the Rural District of St Austell except the civil parishes of St Sampson and Tywardreath, the Rural District of East Kerrier except the civil parishes of Constantine, Mabe, and Perranarworthal, and the Rural District of Truro except the civil parishes of Kea, Kenwyn Rural, Perranzabuloe, St Agnes, St Allen, and Tregavethan.^[1]

The constituency was created by the Reform Act 1832 (the "Great Reform Act") as a replacement for the Penryn constituency, which had become a notoriously rotten borough. The new borough consisted of Penryn, Falmouth and parts of Budock and St Gluvias parishes, giving it a mostly urban population of nearly 12,000, of whom 875 were registered to vote at its first election in 1832.

Initially Penryn and Falmouth elected two MPs, but this was reduced to one in 1885. It was one of the smallest constituencies in England for the next thirty years. At this period its voters were politically unpredictable; though generally among the more Conservative Cornish constituencies, they were influenced by personal factors and often swung against the national tide of opinion. Falmouth, which had a stronger non-conformist presence, was the more Liberal part of the constituency in the late 19th century, but was thought to become more Conservative as it developed its economy as a destination seaside resort.

In 1918 the borough was abolished, but the Penryn and Falmouth name was applied to the county constituency in which the two towns were placed. This was a much more extensive constituency, covering the whole of south central Cornwall, including the towns of Truro and St Austell as well a long stretch of coastline. The constituency had a more industrial character (a sixth of the population were engaged in tin mining); the area suffered badly from unemployment in the 1930s, and in 1935 the Labour Party came within 3,031 votes of winning what would have been their first seat in Cornwall.

The constituency was abolished for the 1950 general election, most of its area being moved into the Truro constituency. Penryn and Falmouth were assigned to the new Falmouth and Camborne division.