The goals of this joint SERDP/Office of Naval Research workshop were to assess the present status of acoustic detection and classification efforts and to develop a roadmap for the continued evolution of acoustic sensors and systems for munitions response at underwater sites. Program managers, research scientists, system developers, and remediation managers from 20 institutions and six countries attended the workshop. Proceedings included a review of UXO remediation and mine clearance work supported by SERDP, ESTCP, and ONR; a summary of the highly successful SERDP/ESTCP land-based remediation program, as well as briefs on the Munitions Response underwater research program and ONR’s mine detection and classification programs. This workshop also featured presentations on the inventory of underwater UXO remediation sites, a description of the UXO munitions response program, a review the science and technology of high- and low-frequency acoustic detection and classification, research needs, and future possibilities. Breakout groups worked together to develop perspectives on the current state of underwater UXO research, directions for the future, and future system requirements. Technology descriptions, discussions, and recommendations going forward can be found in the Workshop Report.