The Unicorn Preservation Society is to receive £45,000 to help restore and repair the famous ship.
The grant of £44,993 is being made by the Sita Trust, which allocates money from landfill operators to good causes.
Mike Clark, chairman of the Unicorn Preservation Society, said: “We are delighted to receive this substantial grant from Sita Trust.
“It will go a long way to ensuring a future for this historic ship. She will become the centre piece of the regeneration of Dundee’s waterfront at City Quay.”
Marianne Ivin of Sita Trust added: “This project really stood out from the crowd with its fantastic history and original community venue status. We are really excited to be able to fund the restoration works on such an iconic ship and look forward to seeing how things progress with its future.”
Sita Trust provides grants through the Scottish Landfill Communities Fund an important source of funding that came into effect in April 2015.
The scheme is linked to the Scottish Landfill Tax and encourages landfill site operators to provide contributions to approved bodies, who can then pass the funds on to community and environmental projects.
The long-term goal of the Unicorn Preservation Society is to repair, maintain, conserve and preserve the Unicorn for learning, and community participation.
Work is needed to prevent significant deterioration of the ship before she can be moved into dry dock.
The Unicorn was launched in 1824 and is the oldest British naval ship still afloat.