East Lothian (/ˈloʊðiən/; Scots: Aest Lowden; Scottish Gaelic: Lodainn an Ear) is a constituency of the Scottish Parliament (Holyrood) covering most of the council area of East Lothian.

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

The other eight constituencies of the South Scotland region are: Ayr, Carrick, Cumnock and Doon Valley, Clydesdale, Dumfriesshire, Ettrick, Roxburgh and Berwickshire, Galloway and West Dumfries, Kilmarnock and Irvine Valley and Midlothian South, Tweeddale and Lauderdale.

[2] Following their first Periodic Review into Scottish Parliament constituencies, the Boundary Commission for Scotland recommended the formation of a modified East Lothian, with the Musselburgh electorate wards part of a redrawn Midlothian North and Musselburgh constituency, which was first used for the 2011 Scottish Parliament election.

The Holyrood constituency covers most of the East Lothian council area.