It was established in 1964 after the amalgamation of Ontario Agricultural College (1874), the MacDonald Institute (1903), and the Ontario Veterinary College (1922), and has since grown to an institution of almost 30,000 students (including those at the Humber campus, Ridgetown campus, off-campus degree enrolments, diploma enrolments and part-time students) and employs 830 full-time faculty (academic staff) as of fall 2019.

[5] Academic achievements include the first scientific validation of water on Mars, Alpha Particle X-ray Spectrometer (APXS) on board the Curiosity rover,[6] and the Barcode of Life project for species identification.

[8] Its first building was Moreton Lodge, located where Johnston Hall now stands, which included classrooms, residences, a library, and a dining room.

[9] [10] The Macdonald Institute was established in 1903 to house women's home economics programs, nature studies, and some domestic art and science.

In 1919 the Ontario Agricultural College aimed at recruiting "farm boys" with a low cost, two-year program ($20.00 per year) and "the lowest possible rate" for room and board.

The University of Guelph Act[14] also brought about the Board of Governors to oversee administrative operations and financial management, and the Senate to address academic concerns.

[12] At one time, courses were offered in English in Guelph, Kemptville and Ridgetown, and in French at Campus d'Alfred near Ottawa.

[20] In 2014, the University of Guelph announced that academic programmes at the Alfred and Kemptville campuses would close after the existing students completed their studies.

This location also offers one-year certificate programs in performance horse handling and veterinary office administration.

[31] Johnston Hall, a signature symbol of the university, was built in 1931, taking the place of the torn-down Moreton Lodge (c. 1874) and becoming the home for the OAC Administration.

The building also overlooks Johnston Green, a popular location for recreational sporting activities and outdoor concerts.

4 Wireless School Association erected a bronze plaque as a war memorial the Royal Canadian Air Force No.

4 Wireless School, which was located on the campus (1941-1945); the plaque honours the memory of their comrades who died in the armed service of Canada during World War II.

The collection consists of mixed media, multimedia and installations, painting, photography, prints and drawings, sculpture, costumes, glass, metalwork, silverwork and goldwork, textiles and tapestries.

This included the top spot in course registration, academic counselling, student residences, information technology, campus atmosphere, environmental commitment and work-play balance.

[52] The magazine stated, "Guelph is considered one of Canada’s top universities for its rigorous academic offerings combined with experiential learning and research training".

Other initiatives include development of air filters for crewed spacecraft and research on changes in skin sensitivity and balance experienced by astronauts in space.

It is responsible for the general business and administration of the University, including finance, capital planning, human resources and ancillary services.

[65] In 2020, the university track-and-field head coach David Scott-Thomas was given a lifetime ban by Athletics Canada for violating its code of conduct.

[68][69] The university faced heavy criticism over its handling of the scandal when the reporting revealed that the administration had been aware of the allegations since 2006, but did little to address them and continued to employ the coach.

"[72][73] In 2021, a group of alumni from the university track and field program wrote an open letter expressing concerns that "the systems that enabled the health and well-being of many athletes to be harmed by individuals in positions of power are still in place," and urging the university "to undertake an independent, comprehensive, and transparent investigation to determine how its existing policies failed to protect student-athletes from an abusive environment.

"[74] Old Jeremiah is the name of an antique British naval gun that rests along Winegard Walk in Branion Plaza, at the heart of the University of Guelph campus.

After World War I, the gun's barrel was plugged and it was brought to campus by students as a sign of remembrance for those lost in battle.

Eventually, fed up with the movement of Old Jeremiah, university officials cemented the cannon in place where it sits today.

However, as a final stab at humour, a group of students shifted the still-mobile direction of the cannon's face, and aimed it at the fourth floor of the University Center, home of the institution's senior administration.

Calling it "[her] form of sculpture", Johnston completed the project over a week's time within a wooden enclosure to avoid the watchful eyes of passing students.

Some students were upset about the removal, claiming Johnston was "taking away [their] history", although the project was done with the approval of university faculty.

For a weekend each March, every part of the campus and its programs is exhibited to the public, from the barns of the Agricultural College to the sugar bush in the arboretum.

The Cannon[79] is an online website co-founded by The Guelph Campus Co-operative and the CSA created for and funded by undergraduate students.

Founded in September 2002, the site has features such as Rate-a-Prof, where students share insight and opinions about professors, and a free classifieds section, available as a means of buying and selling used textbooks and course materials.