Under pressure from gun control advocates, Facebook has agreed to delete posts from users selling illegal guns or offering weapons for sale without background checks.
The social networking site says a similar policy will apply to Instagram, its photo-sharing platform.
The policies announced Wednesday will be implemented over the next few weeks.
Social media expert Lauren Brengarth said Facebook is trying to protect itself, and not push a political agenda.
"All reputable social media sites need to be careful of protecting children," said Brengarth. "It really seems like a legal issue and not so much of a political issue."
If someone is promoting a private gun sale, Facebook will now send the user a message reminding them of current laws. Only people over 18 will be able to see posts advertising gun sales. Pages that promote private gun sales must also include information about laws and regulations.
Also, Facebook said it will remove posts regarding buying or selling guns that indicate an attempt to evade the law, including interstate sales without a licensed firearm dealer involved.
"I really look at this as a victory," said firearms seller Paul Paradis.
Paradis owns Paradise Sales in Colorado Springs. He said the new rules won't infringe on Colorado gun owners' rights.
"They did something that's honestly realistic. It's just advising people what the laws are," said Paradis.
People in Southern Colorado sounded off on Facebook.
"Facebook should be more concerned with nasty words and pictures than with gun control," said Rick Betz from Pueblo on Facebook.
"Law is the law, if you're not breaking it then it shouldn't bother you," said Donnie Anthony on Facebook.
New York Attorney General Eric Schneiderman and gun control groups have been talking to Facebook to get restrictions.
The state requires a federal background check for private gun sales and prohibits selling some popular firearms, such as the AR-15.