Celtic Connections is celebrating its 25th anniversary, featuring more than 2,000 musicians from across the globe.
Over the next 18 days, this year's festival will feature concerts, ceilidhs, exhibitions, workshops and one-off musical collaborations.
The programme of over 300 events will take place across 28 stages and venues including the SSE Hyrdo.
The festival began in 1994 with just one venue and has grown into one of the biggest winter music festivals.
Donald Shaw, the festival's artistic director, said: "I think it was very much an experiment and a way to fill the hall over a quiet time of year.
"It coincided with the beginning of an amazing resurgence in traditional and folk music in Scotland and that's what has been the backbone of its success."
Mr Shaw says the festival's huge international reputation has made his job easier because getting artists to come is half the battle.
"I think it would be very difficult to transplant this festival to another city around the world. I think Glasgow is really suited to how this festival runs. It is an incredible city for music generally and audiences are great and we have tried to build up a reputation for being creative with the shows."
Celebrations begin with a 25th anniversary concert featuring a number of artists including pianist Dave Milligan, who himself performed at that very first festival.
Mr Shaw said: "Even though we have the major headline shows, and even venues like the Hydro, on the same night there will be intimate shows going on in places like the Tron or the Piping Centre or the Festival clubs. Again that is part of the character of it, to appeal to all."
The festival is on until Sunday 5 February.