Baker is a common surname of Old English (Anglo-Saxon) origin and Scotland where Gaelic was anglicized.

From England the surname has spread to neighbouring countries such as Wales, Scotland and Ireland, and also to the English speaking areas of the Americas and Oceania where it is also common.

Some people with the surname have used DNA to trace their origins to Celtic countries and specifically to the Baxter sept of the Clan MacMillan in Scotland.

The name was also used for others involved with baking in some way, including the owner of a communal oven in humbler communities.

Scribes and church officials spelt the name as it sounded, and frequently the spelling changed even during the person's own lifetime.