Abstract. In Haitian Creole the lexical item ki shows up when a subject (but not an object) undergoes operator movement in wh-questions, clefts, and relative clauses. We argue that ki is a phonological reflex of agreement between the complementizer and a wh-phrase. More specifically, the complementizer is spelled out as ki if all its features are checked off by a single goal. We demonstrate that this is accomplished only when the operator is a subject.