The Long, later Tylney-Long Baronetcy, of Westminster in the County of London, was a title in the Baronetage of England. It was created in 1662 for Robert Long, with remainder in default of male issue of his own to his nephew James Long and the heirs male of his body. He was the son of Sir Walter Long. Long never married and was succeeded according to the special remainder by his nephew, James, the second Baronet. He was the son of Sir Walter Long. Three of Sir James's grandsons, the third, fourth and fifth Baronets, all succeeded in the title. The latter represented several constituencies in the House of Commons. He married Lady Emma, daughter of Richard Tylney, 1st Earl Tylney (see Earl Tylney). Their son, the sixth Baronet, succeeded to the substantial Tylney estates, including Wanstead Park, on the death of his maternal uncle in 1784 and assumed the additional surname of Tylney. His only son, the eighth Baronet, died young in 1805 and the baronetcy became extinct.
Catherine Tylney-Long, daughter of the seventh Baronet and sister of the eighth and last Baronet, inherited the family estates. She married William Pole-Wellesley, 4th Earl of Mornington, who assumed the additional surnames of Tylney and Long. See Earl of Mornington for further history of this title.
Long, later Tylney-Long baronets, of Westminster (1662)
- Sir Robert Long, 1st Baronet (1598–1673)
- Sir James Long, 2nd Baronet (1617–1692)
- Sir Robert Long, 3rd Baronet (1673–1692)
- Sir Giles Long, 4th Baronet (1675–1698)
- Sir James Long, 5th Baronet (1682–1729)
- Sir Robert Long, 6th Baronet (1705–1767)
- Sir James Tylney-Long, 7th Baronet (1736–1794)
- Sir James Tylney-Long, 8th Baronet (1794–1805)