This paper describes and proposes an analysis of relative clauses in Mẽbengokre, a Jê language from the eastern Amazon region of Brazil. Relative clauses in this language are normally internally-headed, and the verbal predicate within them assumes a nominal form, triggering ergative alignment. The description of relative clauses addresses first ( §2) their internal characteristics, i.e., ergative case marking, absence of morphological marking of the head of the relative clause, absence of some of the TAM categories present in main clauses, and the fact that internal heads can be omitted, yielding "free relative" constructions; §3 describes their external characteristics, i.e., their peculiar distribution within the clause, which often requires displacement to a left-peripheral focus position, the determiners and classifiers that may occur outside of the relative clause, and the possibility of some heads being external to the relative clause, among other topics.The main thrust of our analysis of relative clauses is to show ( §4) that they are not adjuncts of any sort, but rather self-contained noun phrases. In light of this idea, we analyze all "adjectival" modification within a noun phrase as having a predicative structure identical to that of relative clauses. The paper concludes by arguing that the proposed analysis of relative clauses illustrates a striking property of Mẽbengokre, namely the systematic ambiguity between modifiers and heads found in all nominal expressions in the language.