It is run over a distance of 7 furlongs (1,408 metres) at the Curragh in April.
The event is named after Gladness, a successful Irish-trained racehorse in the 1950s.
The Gladness Stakes originally held Listed status.
It was promoted to Group 3 level in 1987, and closed to three-year-olds in 2004.
The race was downgraded to Listed status again from the 2024 running.