Modeling relations and interactions between agents (e.g., objects, robots, and humans) is widely studied and plays an important role in various tasks, necessitating larger-scale communication and collaboration between researchers in different fields. Our goal is to enable interdisciplinary discussion about multi-agent relational reasoning from different research areas such as autonomous driving, visual reasoning, multi-agent systems, object detection and tracking, scene understanding, human-robot interaction, graph representation learning, intuitive physics, dynamics modeling, and cognitive science. The goal of this workshop is to provide an opportunity to discuss how the concepts and techniques in different fields related to multi-agent interaction modeling could help advance each other.