The Portuguese nobility was a social class enshrined in the laws of the Kingdom of Portugal with specific privileges, prerogatives, obligations and regulations. The nobility ranked immediately after royalty and was itself subdivided into a number of subcategories which included the titled nobility and nobility of blood at the top and civic nobility at the bottom, encompassing a small, but not insignificant proportion of Portugal's citizenry.

The Kingdom of Portugal was a monarchy in the western Iberian Peninsula and the predecessor of the modern Portuguese Republic. Existing to various extents between 1139 and 1910, it was also known as the Kingdom of Portugal and the Algarves after 1415, and as the United Kingdom of Portugal, Brazil and the Algarves between 1815 and 1822. The name is also often applied to the Portuguese Empire, the realm's overseas colonies.