Reds legend Gary Neville, who recently took up the role of Environmental Ambassador for the club, said: "Manchester United’s dedication to environmental best practice has progressed well over recent years. I’m very pleased to play my part as an ambassador to support the excellent work by the club’s staff on their various initiatives and campaigns.
"This latest successful certification helps demonstrate real leadership in the growing area of sustainability in the sporting and events industry."
Keith McIntosh, Group HSE Manager for United, praised the hard work of the club’s staff, saying: "I’m delighted that Manchester United has achieved this standard.
"This has been a real team effort across the business and the certification is testament to a lot of hard work across the club."
In recent years, United’s dedication to reducing its carbon emissions was recognised when the club achieved the Carbon Trust Standard and was placed top of the government’s CRC Energy Efficiency Scheme league table.
In February this year, United also became the first football club in England to be awarded the international standard for Environmental Management Systems – ISO14001.
The club has now realised the dream of achieving a treble in this field and become a major stadium in the UK to hold three major sustainability standards: The Carbon Trust Standard, ISO14001 and ISO20121.