Midlothian South, Tweeddale and Lauderdale is a constituency of the Scottish Parliament (Holyrood) covering parts of the council areas of Midlothian and Scottish Borders.

It is one of nine constituencies in the South Scotland electoral region, which elects seven additional members, in addition to nine constituency MSPs, to produce a form of proportional representation for the region as a whole.

The remainder of Midlothian council area lies within the constituency of Midlothian North and Musselburgh, whilst the remainder of Scottish Borders forms the Ettrick, Roxburgh and Berwickshire constituency.

[2][3] The other eight constituencies of the South Scotland region are: Ayr, Carrick, Cumnock and Doon Valley, Clydesdale, Dumfriesshire, East Lothian, Ettrick, Roxburgh and Berwickshire, Galloway and West Dumfries and Kilmarnock and Irvine Valley.

Since the 2011 Scottish Parliament election, the constituency of Midlothian South, Tweeddale and Lauderdale has been formed from the following electoral wards:[3]