Sian Mary Williams (born November 28, 1964 in Eastbourne, Sussex) is a television presenter for the BBC.
Prior to her broadcasting career she spent more than a decade in radio as a producer for news and current affairs programmes. Joining the BBC News 24 service as an editor, she went on to become a presenter after being offered the 4–7pm slot with Gavin Esler.
She joined BBC's Breakfast in 2001 as one of its regular presenters, usually co-hosting with Dermot Murnaghan or Bill Turnbull. As well as presenting Breakfast (from which she took a break in 2004), she also appears as a newsreader on the Six O'Clock News, has a regular slot on BBC Radio 5 Live, and a weekly TV arts show for BBC Wales.
Sian returned to Breakfast early in 2005 after a spell as presenter on the BBC's 6 O'clock News.
She was immediately sent to Sri Lanka where she presented a week of special programmes following the tsunami.
She rounded off that week by flying to Phuket in Thailand and managed to grab an interview with the Foreign Secretary Jack Straw live on Breakfast.
Although born and raised in England, Williams is Welsh by heritage, her family hailing from Llanelli.