Lisa Jane Weightman (born 16 January 1979) is an Australian long distance runner and four time Olympian who specializes in the marathon event.

At the 2020 Tokyo Olympics she came 26th in the Women's marathon with a time of 2:34.19, 7 minutes behind the eventual winner, Peres Jepchirchir.

Weightman started out as a track runner but had her first success in cross country running, winning the under-23 section of the national championships in 2003.

In 2006, she became a double national champion when she topped the podium in the 10,000 metres and half marathon events, and she returned to the Chiba Ekiden to improve to fourth place in her stage.

[10][11] At the 2009 Christchurch Half Marathon, she was the first past the post to record her first major win on the road running circuit.

[12] She competed at her first World Championships in Athletics later that season as Australia's only participant in the women's marathon; she placed eighteenth overall and set a new personal best over the distance with a time of 2:30:42.