But what is the ozone layer and why is it important?
The ozone layer is the part of the Earth's upper atmosphere where ozone, a form of oxygen gas, is found.
It absorbs UV radiation, preventing most of it from reaching us on the ground. This is important as UV radiation can harm humans, animals and plants.
Scientists first noticed a dramatic thinning of ozone above Antarctica in the 1980s.
It was being destroyed by gases called CFCs that were found in things like hairsprays, fridges and air conditioning units.
The scientists say that in September 2015 the hole had shrunk by 4 million sq km since the year 2000 - an area roughly the size of India.
They think it's because CFC gasses were banned around the world.
The hole in the ozone layer above Antarctica is starting to get smaller, according to scientists.