Thomas Wriothesley, 4th Earl of Southampton, KG (/ˈraɪəθsli/ RY-əth-slee;[1] 10 March 1607 – 16 May 1667), styled Lord Wriothesley before 1624, was an English statesman, a staunch supporter of King Charles II who after the Restoration of the Monarchy in 1660 rose to the position of Lord High Treasurer, which term began with the assumption of power by the Clarendon Ministry.

He "was remarkable for his freedom from any taint of corruption and for his efforts in the interests of economy and financial order",[2] a noble if not a completely objective view of his work as the keeper of the nation's finances.

In 1545 King Henry VIII granted to his ancestor Thomas Wriothesley, 1st Earl of Southampton, Chancellor of England, the manor of Bloomsbury[4] (now in Central London), which descended by the 4th Earl's second daughter and heiress to the Russell family, and is now part of the Bedford Estate.

Samuel Pepys admired Southampton's integrity and the stoicism with which he endured his painful last illness, but clearly had doubts about his competence as Treasurer; in particular, he recorded Southampton's despairing words to him, having been asked to raise more funds at a Council meeting in April 1665: "Why, what means all this, Mr. Pepys?

Coventry recalled that other ministers would joke that regardless of his complaints that it was "impossible" to find money, Southampton always succeeded in the end.