At the Seventh Review Conference of the Biological and Toxin Weapons Convention (BTWC) in December 2011, a debate was initiated on the potential of developing a peer-review system to build confidence in the implementation of the Convention. Peer review has precedent in the activities of a number of international organizations, although the objectives, format, participants, and structure of the mechanisms vary. This study takes the debate forward by looking at what peer review is, how it works elsewhere, how it could be applied in the context of the BTWC, what would be required to move forward, and what possible advantages or disadvantages a peer-review process would confer to the BTWC in light of the Convention's recent history.