The decision on the procurement arrangement was made at a meeting between the defense chiefs of the three countries.
The Carl Gustaf recoilless rifle is an 84mm man-portable, reusable weapon produced by Saab.
"The joint ammunition procurement helps to save taxpayer's money in each of the Baltic States because a larger quantity means a smaller price," said Estonian Defense Minister Urmas Reinsalu. "This procurement will ensure that our defense forces have the ammunition reserves necessary to increase our defense capability."
The amount of 84mm ammunition that will be jointly ordered wasn't disclosed.
The Estonian Ministry of Defense said the three ministers also decided that in 2016 Estonia, Latvia and Lithuania will contribute at least one joint battalion-sized unit to the NATO Response Force and will increase funding for the Host Nation Support, part of NATO's smart defense initiative for member air defense.
"Funds of the HNS-package will be used to pay, in part, for the fuel used by allied fighter aircraft, and for the housing and transport costs of allied troops," the ministry said.