Rosamund Jane Lupton (née Orde-Powlett), is a British writer. She studied literature at Cambridge University. She is perhaps best known for her novels Sister, Afterwards, The Quality of Silence and Three Hours.

Three Hours was chosen by the Times as their thriller of the year. The Sunday Times called it "a brilliant literary thriller... reminiscent of both Greek tragedy and Shakespeare." Ruth Jones, author and actress, praised it as "gob-smackingly, heart-stoppingly, breath-holdingly brilliant.. the tension will blow your mind...."

Her debut novel, Sister, was a BBC Radio 4 Book at Bedtime, a Sunday Times and New York Times best seller, and the fastest selling debut in WHSmiths.