Herein we describe the QuickWoZ system, a Wizard-of-Oz (WoZ) tool that allows for the remote control of the behavior of animated characters in a 3D environment. The complete scene, character, behaviors and sounds can be defined in simple XML documents, which are parsed at runtime, so that setting up an experiment can be done without programming expertise. Quick selection lists and buttons enable the wizard to easily control the agents’ behavior and allow for fast reactions to the subjects’ input. The system is tailored for experiments with embodied conversational agents (ECAs) featuring multimodal interaction and was designed as a rapid prototyping system for evaluating the impact of an agent’s behavior on the user.