This study examines the latest attempt to bring an end to one of Asia’s longest-running separatist conflicts. In August 2005 in Finland, representatives of the Indonesian government and the Free Aceh Movement signed an agreement which sets down the outline of a comprehensive settlement to the Aceh conflict. Until recently, this conflict had appeared close to intractable. Earlier attempts to reach a negotiated settlement between 2000 and 2003 broke down in acrimony and the Indonesian government launched a military offensive, vowing to wipe out the rebels once and for all. Why did the two parties agree to resume talks so soon after the earlier failures? And what are the chances that the peace agreement will hold this time? Written by a leading expert on the Aceh conflict, this study examines the factors that prompted the belligerents to return to the negotiating table, surveys the course of the negotiations, analyses the deal itself and identifies potential spoilers. It concludes that the Helsinki agreement represents Aceh’s best chance for peace since the separatist insurgency began almost thirty years ago. The deal is more comprehensive than earlier agreements and its monitoring provisions are more robust. There is also more good will on both sides, based partly on greater awareness that previous violent strategies had failed. Even so, there are powerful forces opposed to the deal, and backsliding or equivocation on either side could easily prompt a return to violence if implementation is not managed skillfully. This is the twentieth publication in Policy Studies, a peer-reviewed East-West Center Washington series that presents scholarly analysis of key contemporary domestic and international political, economic, and strategic issues affecting Asia in a policy relevant manner.