Cairn Homes has agreed to buy part of RTÉ's Donnnybrook campus for €107.5m.
This is far in excess of the €75m guide price set for the just under nine-acre site by estate agents Savills.
Cairn commented that the Dublin 4 location was a "prime site in a unique location which has strong potential for apartment development."
It is planning to build up to 500 apartments and nine houses, with the transaction expected to close next month.
RTÉ Director General Dee Forbes said the broadcaster had to sell the land due to the vastly reduced commercial and licence fee income it is now operating on.
The funds will be invested in capital projects, including technology upgrades and key digital infrastructure.