The last decade has witnessed an increasing interest in the study of acoustic/elastic metamaterials and their potential engineering applications. Acoustic/elastic metamaterials are a class of composite materials deliberately designed to have unusual effective material properties not readily found in nature. They considerably extend the allowed range of material properties and lead to unprecedented possibilities for material design and control of wave motion. They offer a novel solution for elastic and acoustic wave attenuation, vibration/wave cloaking and earthquake protection, etc. The objective of this symposium is to provide a platform for an inter-disciplinary exchange of ideas and recent progress of acoustic/elastic metamaterials between scholars and engineers in the fields of solid mechanics, wave mechanics, physics and material science.