There have been two Baronetcies created for persons with the surname Mostyn, both in the Baronetage of England. One creation is extant as of 2008.

The Mostyn Baronetcy, of Mostyn

Mostyn

Mostyn is a small village in Flintshire, North Wales, lying on the estuary of the River Dee, and located near the town of Holywell.Mostyn once served as a port from which ferries used to sail to Dublin on the Liverpool-Dublin route...

 in the County of Flint

Flintshire

Flintshire is a county in north-east Wales. It borders Denbighshire, Wrexham and the English county of Cheshire. It is named after the historic county of Flintshire, which had notably different borders...

, was created in the Baronetage of England on 3 August 1660 for Roger Mostyn. 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 Carnarvon. The third Baronet represented Flintshire

Flintshire (UK Parliament constituency)

Flintshire was a parliamentary constituency in North-East Wales which returned one Member of Parliament to the House of Commons of the Parliament of the United Kingdom from 1542 until it was abolished for the 1950 general election.- Boundaries :...

, Flint

Flint Boroughs (UK Parliament constituency)

Flint Boroughs was a parliamentary constituency in north-east Wales which returned one Member of Parliament to the House of Commons of the Parliament of the United Kingdom and its predecessors, from 1542 until it was abolished for the 1918 general election.-Boundaries:From its first known general...

 and Cheshire

Cheshire (UK Parliament constituency)

Cheshire is a former United Kingdom Parliamentiary constituency for the county of Cheshire. 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 1832.As a county...

 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...

 and served as Lord-Lieutenant of Flintshire.