Ella Pallister was a student at Thomas Hardye School in Dorchester.
In a statement the school said: "We are devastated by the news of the tragic and sudden death of Ella Pallister.
"She was studying in Year 13 and she was a popular, bubbly, hard- working and caring student.
"Her closest friends are in shock, but the whole sixth form and school community are grieving for her loss.
"Our thoughts and condolences are with her family at this very sad time."
Ella Pallister's parents have paid tribute to her and her love of horse riding saying "Ella was our shining star.
"All she has ever wanted was to ride her ponies and win her competitions in the fastest time possible".
The 17 year old died after she fell from a horse in Dorset on Sunday.
Ella Pallister from Portesham in Dorset was competing near Dorchester on Sunday when she fell from her horse. The seventeen year old was flown to Southampton General Hospital, where she died.
British Showjumping have confirmed that 17 year old Ella Pallister, from Dorset died yesterday as a result of an injury sustained whilst competing at a British Showjumping affiliated show at Kingston Maurward in Dorset on Sunday.
Ella fell from her horse in the warm-up arena and was transferred to Dorchester Hospital prior to being taken by Air Ambulance to Southampton Hospital.Both British Showjumping and Kingston Maurward said on their website that they extended their condolences to the family during this difficult time.