The new policy is set to go into effect from June 21, it said.
The announcement comes as the US has been embroiled in a nationwide debate over gun reform. Mass shootings, including school attacks in Parkland, Florida, and Santa Fe, Texas, have intensified the discussion.
Facebook is not the only Silicon Valley company that's waded into the gun debate by restricting the content on its platforms.
In March, YouTube, owned by Google, said it will ban videos that promote or link to websites that sell firearms and accessories. The company had already banned videos that attempted to sell firearms.
Facebook's advertising and data collection policies have more broadly been under scrutiny as the company deals with the toughest crises in its 14-year history.
In March, the social network was criticised for a scandal involving Cambridge Analytica, the British political consulting firm, which improperly accessed personal information on up to 87 million Facebook users.
Facebook's updated advertisements policy could ruffle conservatives and Second Amendment advocates. Some conservatives are already suspicious of Facebook, accusing the social network of liberal bias and suppression of conservative voices.
On Friday, Facebook updated its advertising policy page with examples of what kinds of firearm ads are and are not allowed on the platform.
Facebook said that in the weeks ahead it will work with businesses and organisations that may be affected by the new age restriction policy.
Business Standard has always strived hard to provide up-to-date information and commentary on developments that are of interest to you and have wider political and economic implications for the country and the world. Your encouragement and constant feedback on how to improve our offering have only made our resolve and commitment to these ideals stronger. Even during these difficult times arising out of Covid-19, we continue to remain committed to keeping you informed and updated with credible news, authoritative views and incisive commentary on topical issues of relevance.
We, however, have a request.
As we battle the economic impact of the pandemic, we need your support even more, so that we can continue to offer you more quality content. Our subscription model has seen an encouraging response from many of you, who have subscribed to our online content. More subscription to our online content can only help us achieve the goals of offering you even better and more relevant content. We believe in free, fair and credible journalism. Your support through more subscriptions can help us practise the journalism to which we are committed.
Support quality journalism and subscribe to Business Standard.