Politicians in Europe have lifted a ban stopping countries in the European Union from supplying weapons to Syria.
This means that EU countries can now send weapons into Syria, to arm the rebels who are fighting the government.
The idea is that giving more arms to the rebels may help them to win their war against the Syrian leaders.
But Russia has criticised the decision and has said it will provide more weapons for Syria's government forces.
Fierce fighting between rebels and the government forces in the country has been going on there for more than two years, killing over 90,000 people.
Before today, a ban stopping countries in the EU from supplying weapons to Syria has meant the UK has only been able to send in non lethal equipment like vehicles and communication tools.
Almost half a million children and their families have been forced to leave Syria and seek refuge in neighbouring countries since the conflict began.
To find out more about what's happening in the country, read Newsround's guide to Syria.