William Ashburnham, 2nd Baron Ashburnham (21 May 1679 – 16 June 1710) was an English landowner and politician.
Ashburnham was the eldest son of John Ashburnham, 1st Baron Ashburnham, and Bridget, daughter of Walter Vaughan, of Porthammel House, Brecknockshire. He sat as Member of Parliament for Hastings from 1702 to 1710, a seat previously held by his father. In January 1710 he succeeded his father in the barony and antered the House of Lords. He was also briefly Custos Rotulorum of Brecknockshire in 1710.
Lord Ashburnham married Catherine, daughter of Thomas Taylor, of Clapham, Bedfordshire, in 1705. The marriage was childless. He died at Ashburnham on 16 June 1710, aged 31, from smallpox, and was succeeded by his younger brother, John. Lady Ashburnham died from the same disease less than a month later, aged 23.