Eilidh MacLeod, from Barra, was one of 22 people killed in the terror attack at an Ariana Grande concert in May last year.
Members of her family are raising money to build the memorial on the Outer Hebrides island by taking part in the Great Manchester Run over 10km.
The family has already raised £4,000 for the memorial on Barra.
MacLeod was just 14 when she was killed.
Her friend, Laura MacIntyre, 15, was also injured in the terrorist attack
MacLeod’s family have been training for the run in Cheshire, where many of them live.
Her great-uncle Donald Manford told STV: “It’s an enormous privilege to see a community come together to show solidarity, showcasing everything they have.
“There couldn’t be a greater tribute.”
Emily White, MacLeod’s cousin, said: “She was amazing. She was bubbly and happy ... and now she’s bringing us together.”