The third CAIR workshop brings together researchers and developers interested in advancing conversational systems in interactive information retrieval. The workshop builds on the first and second CAIR workshops held at SIGIR 2017 and 2018 and will focus on the continuing development of current challenges, user and system limitations, and evaluation of conversational systems for information retrieval. Participants will collaboratively explore different contexts (i.e., home, hospitals, or work settings), use cases, and interactivity forms (voice-only, multi-modal, screen-based) in which conversational search systems can be used. Possible outcomes include fostering novel and innovative methodologies (such as for data collection and evaluation), personalising conversational systems, and understanding ethical challenges—such as system transparency—from the user’s perspective.