The event is being held at its familiar home of Glasgow Green this weekend. It is the first time the annual gathering is being held over two days.
Overall, 225 bands are taking part in the event, which is expected to be attended by thousands of spectators today and tomorrow.
The gates opened at 8am today, with the competition beginning at 10am.
An event spokesman said there was already a “great” atmosphere at the site, despite some morning rain.
The event involves competitions across all grades, as well as a fiercely contested drum major contest and Highland dancing.
Last year’s overall winner was the Field Marshal Montgomery Pipe Band from Northern Ireland, which also won the 2011 competition. This year’s winners should be known by tomorrow evening.
The championships, affectionately known as The Worlds, have been associated with Glasgow for more than 60 years.
Yesterday, pipers marched through the city in a traditional curtain-raiser to the event. Four bands - Sons of Scotland from Canada, St Johns College from Zimbabwe, St Patricks Battalion Pipes & Drums from Mexico and Catamount from the US - got the music started in a parade from St Enoch Square to George Square.
The event is organised by Glasgow Life in association with the Royal Scottish Pipe Band Association.