The Janssen Baronetcy, of Wimbledon in the County of Surrey, was a title in the Baronetage of Great Britain. It was created on 11 March 1715 for the Dutch-born financier Theodore Janssen

Sir Theodore Janssen, 1st Baronet

Sir Theodore Janssen of Wimbledon, 1st Baronet was a Dutch-born English financier and Member of Parliament who after a long and successful career in commerce was ruined and disgraced by his part in the South Sea Bubble....

, who also represented Yarmouth

Yarmouth (Isle of Wight) (UK Parliament constituency)

Yarmouth was a borough constituency of the House of Commons of England then of the House of Commons of Great Britain from 1707 to 1800 and of the House of Commons of the United Kingdom from 1801 to 1832...

 in the House of Commons

British House of Commons

The House of Commons is the lower house of the Parliament of the United Kingdom, which also comprises the Sovereign and the House of Lords . Both Commons and Lords meet in the Palace of Westminster. The Commons is a democratically elected body, consisting of 650 members , who are known as Members...

. The second Baronet sat as Member of Parliament

Member of Parliament

A Member of Parliament is a representative of the voters to a :parliament. In many countries with bicameral parliaments, the term applies specifically to members of the lower house, as upper houses often have a different title, such as senate, and thus also have different titles for its members,...

 for Dorchester

Dorchester (UK Parliament constituency)

Dorchester was a parliamentary constituency centred on the town of Dorchester in Dorset. It returned two Members of Parliament to the House of Commons of the Parliament of the United Kingdom from 1295 to 1868, when its representation was reduced one member....

 while the fourth and last Baronet was Member of Parliament for the City of London

City of London (UK Parliament constituency)

The City of London was a United Kingdom Parliamentary constituency. It was a constituency of the House of Commons of the Parliament of England then of the Parliament of Great Britain from 1707 to 1800 and of the Parliament of the United Kingdom from 1801 to 1950.-Boundaries and boundary...

 and a Lord Mayor of London

Lord Mayor of London

The Right Honourable Lord Mayor of London is the legal title for the Mayor of the City of London Corporation. The Lord Mayor of London is to be distinguished from the Mayor of London; the former is an officer only of the City of London, while the Mayor of London is the Mayor of Greater London and...

. The title became extinct on the latter's death in 1777.

The last baronet's daughter Henrietta Janssen (d. 29 July 1840 Twickenham

Twickenham

Twickenham is a large suburban town southwest of central London. It is the administrative headquarters of the London Borough of Richmond upon Thames and one of the locally important district centres identified in the London Plan...

, aged 87) married Lorenzo Moore, MP for Dungannon

Dungannon (Parliament of Ireland constituency)

Dungannon was a constituency represented in the Irish House of Commons until 1800.-History:In the Patriot Parliament of 1689 summoned by King James II, Dungannon was represented with two members.-1689–1801:...

 in Ireland, and had issue including General Sir Lorenzo Moore, whose daughter Zakyntha married into the Boyle family in 1849.

Jansen Baronets, of Wimbledon (1715)

• Sir Theodore Janssen, 1st Baronet
  Sir Theodore Janssen, 1st Baronet
  Sir Theodore Janssen of Wimbledon, 1st Baronet was a Dutch-born English financier and Member of Parliament who after a long and successful career in commerce was ruined and disgraced by his part in the South Sea Bubble....
  
   (c. 1658-1748)
• Sir Abraham Janssen, 2nd Baronet (c. 1699-1765)
• Sir Henry Janssen, 3rd Baronet (d. 1766)
• Sir Stephen Theodore Janssen, 4th Baronet (d. 1777)