In Scotland a sheriff principal (pl. sheriffs principal) (Scottish Gaelic: àrd-siorram) is a judge in charge of a sheriffdom with judicial, quasi-judicial, and administrative responsibilities. Sheriffs principal have been part of the judiciary of Scotland since the 11th century. Sheriffs principal were originally appointed by the monarch of Scotland, and evolved into a heritable jurisdiction before appointment was again vested in the Crown and the monarch of the United Kingdom following the passage of the Heritable Jurisdictions (Scotland) Act 1746.

Under the Sheriff Courts (Scotland) Act 1971 (as amended), each sheriff principal is appointed by the monarch of the United Kingdom on the advice of the First Minister of Scotland, who is advised by the Judicial Appointments Board for Scotland. As of May 2017 there were six sheriffs principal, each of whom has responsibility not only as a judge, but for the administration of justice in their respective sheriffdoms. Sheriffs principal have to ensure the effective running of the sheriff courts and justice of the peace courts within their jurisdiction. Following the passage of both the Courts Reform (Scotland) Act 2014 and the Judiciary and Courts (Scotland) Act 2008, sheriffs principal are subject to the authority and direction of the Lord President of the Court of Session as Head of the Judiciary of Scotland.

Sheriffs principal hold additional judicial offices, including the Sheriff Principal of Lothian and Borders who is Sheriff in Chancery, and President of the Sheriff Personal Injury Court. All of the sheriffs principal are Appeal Sheriffs and ex officio members of the Sheriff Appeal Court.

Outside their judicial office, each sheriff principal holds several other offices ex officio, including Commissioner of Northern Lighthouses and General Commissioner of Income Tax, with each sheriff principal having a ceremonial role in their respective sheriffdom that means they outrank all but members of the royal family and the Lord Lieutenant.

The history of the sheriffs principal in Scotland is much confused because over time different names were used to refer to sheriffs. Sheriffs principal are those sheriffs who have held office over a sheriffdom, whether through inheritance or through direct appointment by the Crown. Thus, hereditary sheriff (before 1746) and sheriff-depute (after 1746) are the precursors to the modern office of sheriff principal. The precursor to the modern office of sheriff was historically referred to as sheriff substitute.

David I, King of Scots from 1124 to 1153, appointed sheriffs as administrators and judges throughout Scotland. Such officers eventually became hereditary with a sheriff-depute appointed to undertake the actual judicial work of the office. It is from these sheriffs that the modern day office of sheriffs principal derives, with a final settlement on the name by the Sheriff Courts (Scotland) Act 1971. The modern day office of sheriff derives from the sheriffs-substitute that were appointed by the sheriffs-depute (now sheriffs principal.)

In 1540 an Act of the Parliament of Scotland^[which?] mandated that sheriffs principal (along with bailies and stewards) should "hold all their three head courts by themselves in proper person, unless they have a just and lawful excuse". However, in the 16th century it appears that sheriffs-depute held office entirely at the will of the sheriffs principal, and undertook the vast majority of judicial work.

In the 17th century, under the reign of Charles II, the number of heritable sheriffs principal increased in recognition of his restoration to the throne. By 1700, 21 of the 33 sheriffs principal were hereditary.