The Williams, later Williams-Bulkeley Baronetcy, of Penrhyn in the County of Caernarvon, is a title in the Baronetage of England. It was created on 17 June 1661 for Griffith Williams. He had already been granted a baronetcy by Oliver Cromwell in 1658. The second Baronet represented both Caernarvonshire and Caernarvon in the House of Commons. The eighth Baronet sat as Member of Parliament for Beaumaris while the ninth Baronet represented Caernarvonshire and Beaumaris. The tenth Baronet was Member of Parliament for Beaumaris, Anglesey and Flint Burghs and served as Lord Lieutenant of Caernarvonshire. In 1826 he assumed by Royal licence the additional surname of Bulkeley on succeeding to the estates of Thomas James Bulkeley, 7th Viscount Bulkeley. The twelfth and thirteenth Baronets were both Lord Lieutenant of Anglesey while the latter was also Lord Lieutenant of Gwynedd.
The family seat is Baron Hill, Anglesey.