The Eastbourne-based print and design company achieved carbon neutral status early in 2008 and was awarded FSC and PEFC accreditation later that year.
Chief executive Graham Brownett said: "Much of the work for this project involved documenting evidence of our already streamlined and quality-focused working practices.
"This award recognises our commitment as commercial printers to minimising our impact on the environment and adds value to our proposition where not only quality of service, but also green credentials count."
He said that many of the company's customers had taken advantage of its FSC and PEFC certified products, and claimed that the new certification would help grow the business.
"We are proud to reach this milestone, but we will not stop at achieving ISO 14001 accreditation as we are committed to continuous improvement and environmental responsibility," Brownett added.
Manor Creative has 49 staff and turnover close to £4m. It recently installed a Xerox iGen4 digital press, which uses non-toxic dry inks and is made from 97% recyclable components.