Portrait of Countess Blessington is an 1822 portrait painting by the English artist Sir Thomas Lawrence featuring the Irish aristocrat Marguerite Gardiner, Countess of Blessington.

Widowed in 1817 she married the Anglo-Irish Earl Charles Gardiner the following year.

Lawrence was President of the Royal Academy and Britain's leading portraitist when he painted the Countess.

[3] Today the painting is in the Wallace Collection in Manchester Square in Marylebone.

[4] Hanging nearby is another work by Lawrence depicting Lord Hertford, a former owner of the property.