The present study aims to examine the analysis of Persian adjective phrases (APs) within Role and Reference Grammar (RRG) and to appraise the merits and demerits thereof. In RRG, there is no independent AP; therefore, predicative adjectives are considered as PREDICATE inside NUCLEUS of the CLAUSE and attributive adjectives are regarded as modifiers within the periphery of NUCLEUSN. Each type of adjective can, in turn, have its own modifiers as arguments or non-arguments. On the basis of this analysis, attributive APs are represented as predicative APs in a form which is very similar to relative clauses. The exclusion of AP from syntactic analysis enjoys prominent methodological and psycholinguistic advantages as such a theory demonstrates the principle of economy and offers more plausible explanations for first language acquisition as well as easier language processing. The application of RRG analysis to APs in Persian indicates that this theory can well account for such phrases in this language. This is best reflected in the effective analysis of split predicative APs, which serves another advantage for RRG. However, there are still such cases as the representation of split attributive APs which remain controversial thorough investigation.