The Buffer Treaty was a diplomatic agreement that was made by the Romulan Star Empire and the United Federation of Planets.
The treaty led to the establishment of what was later known as the Romulan Neutral Zone after the events of the Romulan War. It allowed the creation of outposts on either side of the Neutral Zone with no limitation set on their number though the crew compliments along with their arrangements were set. (FASA RPG - The Romulans module: The Romulan Way: Game Operations Manual)
- The FASA RPG continuity had the Romulan War after the founding of the Federation, but this contradicts later canon which showed that the UFP did not exist until after the Earth-Romulan War. Thus, in this version, it's likely that the agreement was between the Romulans and either the United Earth, Earth Alliance or the Coalition of Planets.