Mervyn Edward Wingfield, 7th Viscount Powerscourt KP PC (I) (13 October 1836 – 5 June 1904) was an Irish peer. He became Viscount Powerscourt in 1844 on the death of his father Richard Wingfield, 6th Viscount Powerscourt. Through this Wingfield line he was a maternal descendant of the historic Stratford Family.
On 26 April 1864, Wingfield married Lady Julia Coke, the daughter of Thomas Coke, 2nd Earl of Leicester. They had five children:
Powerscourt was appointed a Knight of the Order of St Patrick on 2 August 1871. He was created Baron Powerscourt in the Peerage of the United Kingdom in 1885, enabling him to sit in the House of Lords.
Lord Powerscourt collected paintings as a hobby and published a catalog in 1903 called A description and history of Powerscourt. He sometimes included details about his purchases in his list.
The painting of 'The Broken Eggs' by Jan Steen, according to Lord Powerscourt, shows "portraits of Jan Steen and his friend Van Goyen".