Unity Environmental University is a private university based in New Gloucester, Maine. It offers undergraduate and graduate education based on sustainability science that emphasizes study of the environment and natural resources. Initially founded as a residential school in Unity, Maine, the university expanded into online education in 2016 which grew both its enrollment and number of academic programs. The university moved its online program to the historic Pineland Farms campus in New Gloucester in 2019 and later relocated their administrative headquarters there. Unity Environmental University operates both online and in-person programs. It also operates a farm and indoor growing facility in Thorndike and an outdoor center in Moose River.

The college was founded in 1965 as the Unity Institute of Liberal Arts and Sciences with a faculty of 15 and a student body of 39. The founders, a group of local business people, were looking for ways to counter economic decline in the town of Unity. Two years later, it changed its name to Unity College and in 1969 awarded degrees to its first graduating class of 24. The college's founders had previously considered opening a bowling alley and a sock factory before settling on the college, which didn't adopt an environmental-oriented focus until 1977. It built the first Passivhaus college residence in the U.S. in 2011 and became the first college in the country to divest its endowment of fossil fuels in 2012.

Unity underwent a tumultuous period in the 1980s, when it was placed on probation by its accreditor. President Wilson Hess, a professor who was selected to lead the college in the middle of the crisis, led fundraising efforts to put Unity on a firm financial footing. The college received an unprecedented $10 million gift in 2011 and its endowment has since grown to $18 million. Unity began offering online education in 2016 with its first master's degree, in Professional Science. It began offering undergraduate online programs two years later. In 2020, Unity College closed its Unity campus due to the COVID-19 pandemic in the United States. During the pandemic-related closure, the college announced it would pivot away from a traditional residential model and would consider selling its campus. The proposed sale of the Unity, Maine campus and pivot towards distance education frustrated alumni and some faculty, who accused the school of drifting from its environmental mission. Also in 2020, Beth Bing, a former employee, plead guilty to making unauthorized purchases on her college credit card and using fraudulent email and phone communications. In 2021, President Melik Peter Khoury told the Morning Sentinel that the campus was "never listed for sale" and that it would reopen for the fall term, though two years later it was offered for sale as the school continued its shift towards online education and in-person education in New Gloucester and other sites.

The institution moved its online offices from Unity to New Gloucester in 2019. In 2021, when the fate of the Unity, Maine campus was still uncertain, the college announced a new online and commuter junior college, which is also located in New Gloucester called the Technical Institute for Environmental Professions. The college also moved to New Gloucester. Residential students complete their general education courses online under the college's in-person model and can live on the University of Southern Maine campus forty minutes away in Gorham, Maine, where they can utilize USM's libraries and other facilities.

On February 27, 2023, Unity College announced it would change its name to Unity Environmental University. The new name will be introduced gradually over the next year. In 2023, the university announced it had more than 7,500 students full-time students across all of its educational units with its online programming being hailed as an "uncommon success story."

Past presidents include Mitchell Thomashow, Wilson Hess, and Stephen Mulkey.

Unity is divided into Sustainable Education Business Units rather than schools and colleges like a traditional university. These are:

• Distance Education
• In-person Learning
• Sustainable Ventures
• Technical Institute for Environmental Professions

The Technical Institute for Environmental Professions offers associates degrees, while the Distance Education offers both Bachelor of Science degrees and the Professional Science Master's Degree. Bachelor's degrees are also available from Unity Environmental University at Pineland.

Unity had an athletics program and was a member of the Division II level of the United States Collegiate Athletic Association (USCAA), primarily competing in the Yankee Small College Conference (YSCC) from 2008–09 until 2018–19. Known as the Rams, the athletics program featured both USCAA-sanctioned sports and club sports, including a Woodsman team.

Previously, Unity competed in up to nine intercollegiate varsity sports: Men's sports included basketball, cross country, soccer and track & field; while women's sports included basketball, cross country, soccer, track & field and volleyball. Additionally Unity had a number of club sports: woodsmen's team, ice hockey, indoor soccer, lacrosse, martial arts and ultimate frisbee; plus intramural sports.

The Unity College men's and women's cross-country teams both won the 1996 National Small College Athletic Association (NSCAA) National Championship. These were Unity College's first-ever men's and women's national championship teams. The team was coached by Mark Kibler. The NSCAA was the predecessor of today's United States Collegiate Athletic Association (USCAA). In 1992 the Unity College women's cross country team won the NAIA Division 5 New England Championship.

• Official website
• Official athletics website Archived February 1, 2020, at the Wayback Machine

44°36′14.05″N 69°19′50.90″W / 44.6039028°N 69.3308056°W / 44.6039028; -69.3308056