Communication in social contexts such as courtship and territoriality are crucial for reproductive success and survival in many animals. However, sending and receiving sensory information in these contexts can be profoundly influenced by an individual’s reproductive and hormonal state, particularly in species that cycle in and out of breeding condition. This plasticity can also occur on different temporal scales ranging from rapid changes in seconds to longer seasonal changes over months. Unfortunately, many studies on animal communication at different biological levels do not consider potential modulatory influences that may ultimately influence how individuals produce and perceive signals that lead to appropriate behavioral decisions. This symposium brings together researchers studying different sensory systems in diverse vertebrates, coupled with focus on several classes of modulatory molecules at different levels of biological organization from molecules to whole animal behavior. Since modulatory substances in the body can influence anatomical substrates necessary for production (e.g. sensorimotor and motivational systems) and reception (peripheral sensory organs, brain) of communication signals, it is imperative to examine how these substrates are influenced with an integrative perspective to truly understand the selective pressures driving animal communication. By making researchers in diverse fields aware of this endocrine-mediated plasticity in communication across different animal taxa, various sensory channels, and distinct social contexts, we hope to inspire new research directions and interdisciplinary collaborations to advance the field.