Emirates Airline has built an upmarket area dedicated to wealthy customers who fly business and first class with the international carrier.
Dubai-based Emirates is the only non-domestic airline to have a lounge at the airport and its launch has created 21 jobs.
The airline has been flying in and out of Glasgow Airport for the last 10 years and currently operates two return flights each day.
Emirates president Sir Tim Clark jetted in to officially open the lounge and said: "Our new Emirates Lounge is the largest at the airport and its opening celebrates our decade-long operations and our close ties with Scotland.
"Our passenger numbers have grown as we progressively develop our services into Glasgow Airport.
"The lounge will be an unrivalled premium experience for our customers travelling to destinations such as Bangkok, Perth, Sydney and Singapore, via our hub in Dubai."
The lounge is also being used to showcase a range of Scottish products, including smoked salmon from Loch Fyne, beers from Bellhaven Brewery and the Highland single malt whisky Glenmorangie.
Airport managing director Amanda McMillan welcomed the investment, which will see passengers offered fine wines and gourmet food.
She said: "Emirates' new world-class lounge is a fantastic and welcome addition to Glasgow Airport."
Ms McMillan added: "Just a few weeks ago Emirates became the first airline to bring the world's largest commercial aircraft, the A380, to Scotland."