The Defender Burghley Horse Trials is an annual three-day event held at Burghley House near Stamford, Lincolnshire, England, currently in early September. Defender Burghley Horse Trials is classified by the FEI as one of the seven leading three-day events in the world. It has competition at CCI5*-L level. The prize for first place is currently £110,000. Prize money is given down to 20th place.

Eventing is an equestrian event where a single horse and rider combine and compete against other competitors across the three disciplines of dressage, cross-country, and show jumping. This event has its roots in a comprehensive cavalry test that required mastery of several types of riding. The competition may be run as a one-day event (ODE), where all three events are completed in one day or a three-day event (3DE), which is more commonly now run over four days, with dressage on the first two days, followed by cross-country the next day and then show jumping in reverse order on the final day. Eventing was previously known as Combined Training, and the name persists in many smaller organizations. The term "Combined Training" is sometimes confused with the term "Combined Test", which refers to a combination of just two of the phases, most commonly dressage and show jumping.