The Williams baronetcy, of Castell Deudrath and Borthwen in the County of Merioneth, was created in the Baronetage of the United Kingdom on 28 July 1909 for Osmond Williams, son of David Williams. He sat as Liberal Member of Parliament for Merionethshire from 1900 to 1910, and served as Lord Lieutenant of Merionethshire. The title became extinct with the death of the 2nd Baronet in 2012.