English in Singapore, once seen as a neutral, foreign language with no connection to Singaporean identity, has been gradually transformed over the last two hundred years to become a nativized variety with its own unique lexicon and unique grammar. The origin of certain phonological pro- cesses unique to Singapore English is in particular difficult to trace and break down because of the influence of the multitude of other languages spoken in the area, as well as the interaction between these substrates, particularly as it was shaped through the school system. Further, Singapore English can be roughly broken down into Standard Singapore English (SSE)—an acrolectal form of Singapore English that is fairly similar to Received Pronunciation, with the exception of some phonological processes—and Colloquial Singapore English (CSE)—a mesolectal/basilectal form of Singapore English that can be unintelligible to those who speak other varieties of English. Prior analyses of the phonology of Colloquial Singapore English (which will be the focus of this paper as well) have focused on providing documentation of the variety, in particular through rule- based formalisms. However, rule-based phonology has increasingly been disfavored in our current formal system of generative phonology. Instead, how can we represent phonological processes of CSE in an optimality theory (OT) framework, as opposed to a rule-based, purely descriptive framework? In particular, I will draw from a number of previously-attested OT constraints to describe three phonological phenomena in CSE: (1) vowel monophthongization, (2) de-syllabifying syllabic consonants, and (3) deletion of word-final obstruents. In this paper, I will be proposing a number of constraints that will be ranked accordingly in order to produce the desired outputs from our given inputs.