It is understood that Jack de Bromhead fell from his mount while participating in the Glenbeigh Racing Festival at Rossbeigh beach in County Kerry.
His family has described him as a “one-of-a-kind child who touched all our lives in the best way possible”.
“Our hearts are truly broken,” said his parents.
The Glenbeigh Racing Festival is a popular two-day event in which many young jockeys take part.
The rest of the weekend’s racing was cancelled after the incident at about 17:20 local time on Saturday.