Leah O'Brien

Leah O'Brien (born 29 January 2008) is an Australian sprinter. In 2025, she became Australian junior national record holder over 100 metres and was runner-up over that distance at the senior Australian Athletics Championships.

Career On 8 April 2025, O'Brien won the under-18 girls 100 metres title at the Australian National Junior Athletics Championships in a time of 11.14 seconds (+1.7), breaking Raelene Boyle's under-18 national record set 57 years previously at the 1968 Summer Olympics in Mexico. The time placed her ninth on the global all-time under-18 toplist for 100 metres and also placed her equal-fourth with Sally Pearson on the Australian senior all-time list, only 0.04 seconds behind national record holder Torrie Lewis: only Lewis (11.10 s), Melissa Breen (11.11 s) and Melinda Gainsford-Taylor (11.12 s) having run quicker. Boyle and O'Brien met on ABC Radio after the race with Boyle congratulating O'Brien for breaking her 57 year-old record. O'Brien also won the Australian under-18 national 200 metres title at the same championships, held in Perth, Western Australia, in a time of 23.37 seconds.

On 11 April 2025, she qualified for the open 100 metres semi-finals, competing against senior athletes, at the Australian Athletics Championships in Perth, running 11.31 seconds. The following day, she finished runner-up to Torrie Lewis in the final in a photo-finish, with both athletes credited with a time of 11.24 seconds.

She was selected for the Australian team for the 2025 World Athletics Championships in Tokyo, Japan.

Personal life She is from Perth, Western Australia. She attended Perth College.