Frozen conflicts are today a major challenge for the international stability and security. Often cited as a classic example of a frozen conflict, Nagorno-Karabakh displays however its own particularities. The main objective of this article is two-folded: first, to situate Nagorno-Karabakh within the larger context of the frozen conflicts phenomenon and, secondly, to contribute to an explanatory framework that evaluates the preliminary stages of a frozen conflict, through the different phases of its transformation: escalation, diffusion and third-party intervention. The conclusions emphasize several findings based on this case-study that could be integrated in wider strategies aimed at preventing the emergence of frozen conflicts.