The Queen Mary Stakes is a Group 2 flat horse race in Great Britain open to two-year-old fillies.
It is run at Ascot over a distance of 5 furlongs (1,006 metres), and it is scheduled to take place each year in June.
The event is named after Queen Mary, the consort of King George V. It was established in 1921, and the inaugural running was won by Wild Mint.
The present system of race grading was introduced in 1971, and for a period the Queen Mary Stakes was classed at Group 3 level.
The Queen Mary Stakes is now staged on day two of the five-day Royal Ascot meeting.