MacCormick v Lord Advocate 1953 SC 396 was a Scottish constitutional law case and Scottish legal action on whether Queen Elizabeth II was entitled to use the numeral "II" as her regnal number in Scotland, as there had never been an earlier Elizabeth reigning in Scotland.

There, MacCormick and Hamilton lost their case: it was held that the treaty had no provision concerning the numbering of monarchs—it was part of the royal prerogative, and that they had no title to sue the Crown.

The case was thus constitutionally interesting[2] as the Lord Advocate "conceded this point by admitting that the Parliament of the United Kingdom 'could not' repeal or alter [certain] 'fundamental and essential' conditions" of the Act of Union.

[3] However, the Lord President also held that "there is neither precedent nor authority of any kind for the view that the domestic Courts of either Scotland or England have jurisdiction to determine whether a governmental act of the type here in controversy is or is not conform to the provisions of a Treaty" and "it has not been shown that the Court of Session has authority to entertain the issue sought to be raised".

It has been discussed in a number of later decisions of the courts, notably Gibson v Lord Advocate 1975 SC 136, and the English case of Jackson v Attorney General, [2005] 3 WLR 733.