The Games will feature 17 sports across 11 days of competition with more than 4,500 athletes from 71 nations competing, making the event the biggest Scotland has ever hosted.
The Queen called on those present to “unite” in difficult times as a minute’s silence was held for the victims of the Malaysia Airlines MH17 flight disaster.
Eighty-two of the 298 people who died last week when the plane came down over eastern Ukraine were from Commonwealth nations.
The Malaysian team also entered the stadium with their flag at half-mast and wore black armbands.
“To you, the Commonwealth athletes, I send my good wishes for success in your endeavours. Your accomplishments over the coming days will encourage us all to strengthen the bonds that unite us,” said the Queen.
“You remind us that young people, those under 25 years of age, make up half of our Commonwealth citizens; and it is to you that we entrust our values and our future.
“I offer my sincere thanks to the many organisations and volunteers who have worked diligently to bring these Games to fruition, and indeed to the spectators here in the stadium and to the millions watching on television.
“Together, you all play a part in strengthening our friendships in this modern and vibrant association of nations.
“It now gives me the greatest pleasure to declare the 20th Commonwealth Games open.”
A colourful, nearly three-hour long ceremony began with an exuberant sequence depicting the history of Scotland was followed by live performances from world-renowned Scottish singers Rod Stewart and Susan Boyle.
The Queen then made her entrance, accompanied by Prince Philip, whilst the RAF Red Arrows performed a colourful flyover past the stadium.
Teams from all 71 nations were then paraded, starting with 2010 hosts India and ending with Scotland.
Six-time Olympic gold medallist Chris Hoy carried the Queen’s baton on the final leg of its 100,000 mile journey through all of the Commonwealth nations over the past nine months.
There was a brief moment of farce when the President of the Commonwealth Games Federation Prince Tunku Imran couldn’t remove the Queen’s message from the baton.
However, once the message was finally removed, the Queen hailed Glasgow’s suitability for a competition often known as the “friendly games.”
“Over the past 288 days the baton has visited all the nations and territories of the Commonwealth, crossing every continent in a journey of more than 100,000 miles.
“The baton relay represents a calling together of people from every part of the Commonwealth and serves as a reminder of our shared ideals and ambitions as a diverse, resourceful and cohesive family.
“And now, that baton has arrived here in Glasgow, a city renowned for its dynamic cultural and sporting achievements, for the warmth of its people, for this opening ceremony of the friendly games.”
Scottish First Minister Alex Salmond also welcomed the team athletes and officials to what he described as “Scotland’s scene for 11 days of sport and culture.”
“Welcome to the Commonwealth of nations, welcome to Scotland,” he added.