One of the numerous phonological features that sets Classical Armenian apart from its Indo- European sister languages is the numerous instances of metathesis, many of which center around the Proto-Indo-European segment /*r/. Previous rule-based accounts of this process have failed to achieve a solution which is simultaneously unified, elegant, and well-motivated. The data suggests that this metathesis, rather than being the result of “regular sound change” in definable conditioning environments, may be best understood as the avoidance of dispreferred (i.e. marked) structures. As such, the use of an Optimality Theory (OT; Prince and Smolensky 1993) framework, which is driven by the competition between markedness and faithfulness, may prove more successful. Furthermore, an examination of the phonetic properties and articulatory environments involved implies that it is the nature and behavior of the segment [r] which compels these changes. This can be straightforwardly modeled in OT as the interaction between a pair of contextual markedness constraints on the position of [r] (*#r and *Cr – militating against, respectively, initial- and post-consonantal-[r]) and standard CORRESPONDENCE (faithfulness) constraints. Therefore, using an Optimality Theory analysis, the enigmatic behavior of /r/-metathesis in Classical Armenian becomes the easily-obtained output of a singular, unified phonological development.