Margaret Russell, Baroness Ampthill, CI, GCVO, GBE, DStJ (née Lady Margaret Lygon; 8 October 1874 – 12 December 1957) was an English courtier and Red Cross volunteer, known for her long friendship with Queen Mary.

Lady Ampthill was appointed a Companion of the Order of the Crown of India in 1900 and awarded a gold Kaisar-i-Hind Medal in 1906.

Tall, dignified without being stiff, agreeable and sociable, with just that measure of reserve that adds distinction to personality, living examples of the rare art of deportment, each seemed to enhance the virtues of the other.

Friendship grew spontaneously in this fostering atmosphere, and quickly and surely the official relation between the Queen and her lady was transmuted into an intimate companionship that was only broken by Queen Mary's death.Lady Margaret married Oliver Russell, 2nd Baron Ampthill in Madresfield, Worcestershire on 6 October 1894, two days before her 20th birthday.

The Ampthills had four sons and one daughter:[3] She died in Hammersmith, London, aged 83.