English gentlewoman best known for the letters she wrote to her future husband, William Temple (Temple, Sir William, Baronet), before their marriage. The letters are simply written in an easy, conversational style and present an interesting picture of the life of a young English gentlewoman in the Commonwealth period (1649–60). Lively and tender, they are full of good sense, humour, and keen observation.

The daughter of Sir Peter Osborne, she met William Temple (later Sir William) in 1647, and, despite opposition from both families, they married in 1655. Thereafter she became a devoted wife, as a few surviving letters from later years testify. She bore him nine children, of whom seven died in infancy. A friend of Queen Mary, she was buried in Westminster Abbey.

Sir William Temple preserved the group of letters that were written to him during their courtship between December 1652 and October 1654, and they remained in manuscript until the 19th century. They were sold to the British Museum in 1891. The best edition of them was published in 1928 by G.C. Moore Smith.