The Scoto-Norman surname Sinclair comes from the Clan Sinclair, whose progenitors moved to Scotland and were given the land of Roslin, Midlothian by the King of Scots.

The style "Sinclair" is the most common.

It has its origins in Scotland and is a derivation of the original French de Saint-Clair, although the name has also been styled "Santoclair", "de St. Clair", "Sainclair", "Synklar" and many more across the centuries.

The well-known individuals in this article are listed first alphabetically then by profession.

The following are people with the surname St. Clair, St Clair or Saint Clair, all of which are traditionally pronounced in the same manner as Sinclair: Instances of more than one person with the same name: