The charity UNICEF says 90% of Syrian children need urgent humanitarian aid, an increase of 20% in the last year.
It comes as the conflict in the country nears its tenth anniversary.
Fear, poverty and starvation have become realities of growing up in the war zone.
Speaking in 2016, one child called Saja said: "Before the war, it was safe to go out. We wouldn’t worry if something was going to happen to us.
"Life was really beautiful.
"My friends lost their lives when we were bombed. My friends Fatima, Zahra, Cedra, and Wala'a.
"And me, I lost my leg."
The International Committee of the Red Cross (ICRC) recently released a report about the impact of war on a generation of young Syrians and the human cost of the fighting.
A total of 12,000 children have been killed or injured in the conflict.
Five and a half thousand children, including some as young as seven years old, have been recruited as soldiers.
UNICEF’s Sarah Crowe said: "They’re seeing things that they should never see.
"A child should never have to witness this kind of violence."
The war has displaced millions of people in Syria, which has meant many children having to spend their early years in refugee camps.
There is a struggle to meet their basic needs. Violence, the economic crisis and COVID-19 have pushed families to breaking point.
Safa, a child, speaking in 2015, said: "The ones responsible are the politicians. I want to tell you, politicians, stop this game so we can go back to our country and...so that children who lost their parents can have a future, so we also can have a future.”
UNICEF says it needs nearly $1.5 billion to continue helping Syria’s children, while the cost of the average food basket has more than doubled over the past year.
The charity is calling on people around the world to increase support for some of the world’s most vulnerable young people, to give the children the promise of a brighter future.