Sir William Lowther, 1st Baronet, of Marske

Sir William Lowther, 1st Baronet (4 January 1676 – 6 April 1705) was an English landowner from Marske-by-the-Sea, Yorkshire. He was the eldest son of Anthony Lowther and Margaret Penn, daughter of Sir William Penn.

On 15 June 1697, he was created a baronet.

He married Catherine Preston and had three children:
 * Sir Thomas Lowther, 2nd Baronet (1699–1745)
 * Catherine Lowther
 * Margaret Lowther