More than 40 ex-students attended the event at the old Allan Glen's school building in Cathedral Street.
The building, which opened in 1965 , is currently used by City of Glasgow College and is due to be demolished later this year to make way for that institution's £228million campus.
The exclusive secondary school, which was established by the Allan Glen's Endowment Scholarship Trust in 1853, and closed in 1989, was set up to "give a good practical education and preparation for trades or businesses, to between 40 to 50 boys, the sons of tradesmen or persons in the industrial classes of society."
Notable attendees include artist Charles Rennie Macintosh, writer and actor Dirk Bogarde and Lord Todd of Trumpington.
The event was organised by City of Glasgow College to honour the building's rich heritage and to allow former students the opportunity tour the premises one last time.
The attending alumni donated a book of remembrance which will be put on display when the campus opens.
Mike McCreery, who attended the school until he left in 1958 is now Treasurer of the Allan Glen's Club.
Mr McCreery said: "We currently have more than 500 members in the school club and many of them were delighted that City of Glasgow College invited us along to have one last tour of the building.
"It was also great for us to be able to meet with the people involved with the new college campus as they are the ones who will make sure that the Allan Glen's name is always remembered."
College principal Paul Little said: "It was an honour to have some of the Allan Glen's boys back in the college to see their old school for the last time.
"The building which bears the name has served the college and before that the people of Glasgow well.
"However, we are now looking forward to an exciting new chapter with the building of our campus.
"We will ensure that the Allan Glen name lives on."
Whilst Allan Glen's was originally only set up to accommodate 40 pupils, the new City of Glasgow College campus will be equipped to accommodate more than 40,000 students.