Primero was a popular 16th-century gambling card game. Thought to have been invented in the late 15th century. Etymological reasoning suggest Spain as the country of origin, but the earliest "hard" evidence comes from Italy. It soon spread to most of western Europe and was one of the most popular card games in England.

By the eighteenth century the game had fallen out of popularity, and due to the exact rules never having been written down it is not known precisely how the game was played. However a number of reconstructions of the game have been made, primarily on the basis of books describing playing strategy and references in period literature.

Primero is generally considered to be the direct ancestor of the modern game of poker.

It is thought that primero is closely related to the game of primo visto, although their exact relationship is unknown.