|Abstract:||In this paper we present a Realization Optimality-Theoretic account of full and partial identity of forms, i.e., paradigmatic syncretism and cases in which lexemes share the same inflectional formative. Our approach involves both output-to-output correspondence constraints and realization constraints that associate morphosyntactic feature values with morphophonological forms. We show that Realization Optimality Theory (Xu 2007) offers a unified account of these phenomena. Additionally, we argue that Realization Optimality Theory has advantages over several alternative approaches such as feature impoverishment-plus-insertion (Noyer 1998), rules of referral (Zwicky 1985, Stump 1993), and two different models of OT morphology proposed by Müller (2007, 2008). We argue for an autonomous morphological component and also discuss related issues such as the morphology-phonology interface. We suggest that morphology and phonology are distinct components of the grammatical architecture; morphology precedes phonology by default while the morphological and phonological components overlap to an extent that varies among languages.