Lewes is a constituency^{[n 1]} in East Sussex represented in the House of Commons of the UK Parliament since 2015 by Maria Caulfield, a Conservative.

The constituency includes the town of Lewes, most of the Lewes District, including the coastal towns of Seaford and Newhaven, Polegate and Alfriston all in outer parts of the London Commuter Belt, though with a high number of people who have retired from across the country.^[2] The constituency excludes the District of Lewes District wards of East Saltdean and Telscombe Cliffs, Peacehaven East, Peacehaven North, and Peacehaven West (which since 1997 have been in the Brighton, Kemptown (UK Parliament constituency), and instead includes part of neighbouring Wealden District.

1885–1918: The Borough of Brighton, the Sessional Divisions of Hove and Worthing, and parts of the Sessional Divisions of Lewes and Steyning.

1918–1950: The Borough of Lewes, the Urban Districts of Newhaven, Portslade-by-Sea, and Seaford, and the Rural Districts of Chailey, Newhaven, and Steyning East.

1950–1955: The Borough of Lewes, the Urban Districts of Burgess Hill, Newhaven, and Seaford, the Rural District of Chailey, and parts of the Rural Districts of Cuckfield and Hailsham.

1955–1974: The Borough of Lewes, the Urban Districts of Burgess Hill, Newhaven, and Seaford, the Rural District of Chailey, and part of the Rural District of Cuckfield.

1974–1983: The Borough of Lewes, the Urban Districts of Newhaven and Seaford, the Rural District of Chailey, and part of the Rural District of Hailsham.

1983–1997: The District of Lewes, and the District of Wealden wards of Alfriston, Arlington, and East Dean.

1997–2010: The District of Lewes wards of Barcombe, Chailey, Ditchling, Hamsey, Kingston, Lewes Bridge, Lewes Castle, Lewes Priory, Newhaven Denton, Newhaven Meeching, Newhaven Valley, Newick, Ouse Valley, Plumpton, Ringmer, Seaford Central, Seaford East, Seaford North, Seaford West, and Wivelsfield.

2010–present: The District of Lewes wards of Barcombe and Hamsey, Chailey and Wivelsfield, Ditchling and Westmeston, Kingston, Lewes Bridge, Lewes Castle, Lewes Priory, Newhaven Denton and Meeching, Newhaven Valley, Newick, Ouse Valley and Ringmer, Plumpton, Streat, East Chiltington and St John Without, Seaford Central, Seaford East, Seaford North, Seaford South, and Seaford West. With the District of Wealden wards of Alfriston, Arlington, East Dean, Polegate North, and Polegate South.

The constituency of Lewes has existed since commoners were first summoned to Parliament in 1295, the Model Parliament. This is the county town, though less significant in population today, far surpassed by the City of Brighton and Hove — it has nonetheless been continuously represented since that date.

From 1874 the constituency's electorate in elections sent only Conservative MPs except between 1997 and 2015.

• List of parliamentary constituencies in East Sussex