The smallest horse in the world is just 17 inches (43 cm) tall and weighs 57 lb (26 kg).
Thumbelina (born May 1, 2001, died 2018) was a dwarf miniature horse that held the record for being the smallest horse ever. She was the world’s smallest horse, being 43 centimeters (17 inches) tall and weighing 26 kilograms (57 pounds), according to Guinness World Records.