The Kingdom of Sardinia, also referred to as the Kingdom of Sardinia-Piedmont or Piedmont-Sardinia as a composite state during the Savoyard period, was a country in Southern Europe from the late 13th until the mid-19th century.

The Kingdom of Sardinia is a term used to denote the Savoyard state from 1720 until 1861, which united the island of Sardinia with the mainland possessions of the House of Savoy. Before 1847, only the island of Sardinia proper was part of the Kingdom of Sardinia, while the other mainland possessions were held by the Savoys in their own right, hence forming a composite monarchy and a personal union which was formally referred to as the "States of His Majesty the King of Sardinia". This situation was changed by the Perfect Fusion act of 1847, which created a unitary kingdom. Due to the fact that Piedmont was the seat of power and prominent part of the entity, the state is also referred to as Sardinia-Piedmont or Piedmont-Sardinia and sometimes erroneously as the Kingdom of Piedmont.