The contract awarded came from Witney Town Council and is valued at £300,000 per year for the firm. It begins on 1 January and will run for a period of five years, with an opportunity to extend for a further two.
The market town of Witney - West Oxfordshire's largest - is home to 23,000 inhabitants and situated between Oxford and the Gloucestershire borders on the banks of the Windrush River.
GJG business development director Yvette Etcell will be leading on the contract. She said the firm was delighted to be working with Witney Town Council to provide the area with grounds maintenance.
"We have several other contracts in the area and this win has given us the opportunity to promote local staff into key positions, which is tremendous," she explained. "The operational team at Witney will be contract-specific to develop pride and ownership in their contract and the desire to consistently improve service delivery."
The firm has also started a new three-year contract at Anglia Ruskin University's Chelmsford campus, worth around £150,000.
Up to seven people will work on the contract, including some staff transferred from the previous firm ISS Waterers.
The former site manager for the Milton Park contract in Abingdon is being promoted to manager of the new contract.