Don Valley is a constituency^{[n 1]} in South Yorkshire represented in the House of Commons of the UK Parliament since 2019 by Nick Fletcher of the Conservative Party.^{[n 2]}

Further to the completion of the 2023 Periodic Review of Westminster constituencies, the seat will be subject to boundary changes which will include gain of the Isle of Axholme in the Borough of North Lincolnshire and the loss of Conisbrough to the new constituency of Rawmarsh and Conisbrough. As a consequence, it will be renamed Doncaster East and the Isle of Axholme, to be first contested at the next general election.^[2]

Created in 1918, Don Valley is a former coal mining area which elected only Labour MPs from 1922 to 2019. The seat recorded a strong Brexit vote (69%) in the 2016 referendum.

1918—1950: The Urban Districts of Mexborough and Tickhill, and the Rural Districts of Doncaster and Thorne.

1950—1983: The Urban Districts of Adwick-le-Street, Bentley with Arksey, and Tickhill, and the Rural District of Doncaster.

1983—1997: The Metropolitan Borough of Doncaster wards of Conisbrough, Edlington and Warmsworth, Mexborough, Richmond, Rossington, South East, and Southern Parks.

1997—2010: The Metropolitan Borough of Doncaster wards of Conisbrough, Edlington and Warmsworth, Hatfield, Rossington, South East, and Southern Parks.

2010—present: The Metropolitan Borough of Doncaster wards of Conisbrough and Denaby, Edlington and Warmsworth, Finningley, Hatfield, Rossington, Thorne, and Torne Valley.

The current constituency consists of the southern Borough of Doncaster, from Hatfield and the Humberhead Peatlands Nature Reserve in the north and northeast, through Branton, Auckley, and Rossington, to the Torne Valley electoral ward which consists of Wadworth, Tickhill, Braithwell, and in the west Conisbrough.

In boundary changes which took effect at the 2010 election, Sprotbrough was moved to Doncaster North, while in the east the town of Thorne was moved from Doncaster North into Don Valley.

• List of parliamentary constituencies in South Yorkshire