People from across the region have marched through the streets of Bristol, Bath, Gloucester, Taunton, Exeter and Truro.
Inspired by Swedish schoolgirl Greta Thunberg, thousands of students have walked out of classrooms calling on the Government to make tackling climate change a priority.
Organisers hope today will go down as one of the biggest marches in history. They're aiming to present local councils with lists of environmental and economic demands.
The action has been designed to coincide with a UN emergency climate action summit in New York. A second strike is planned for 27 September.
Where are other strikes taking place?
They have been taking place all over the world, including America, Australia and Germany.
In the West Country, protests were in Bristol, Bath, Gloucester, Taunton, Exeter and Truro.
The main UK strike is at Westminster.
What's it all for?
Greta Thunberg inspired a global movement when she sat in front of the Swedish parliament and demanded action on climate change, inspiring the Fridays for Future movement.
Fridays for Future evolved into the Youth Strike for Climate movement, which says its students are "driven by an alarming lack of Government leadership on climate action over previous decades."
The coalition is calling on the Government to declare "a state of climate emergency" and educate the British public just how serious climate change is.
They're also demanding changes to the school curriculum which will include education about climate change.