The AASHTO Guidelines for Performance-Based Seismic Design of Highway Bridges, First Edition (2023), present a methodology for designing highway bridges to defined seismic performance objectives beyond conventional life safety requirements. An opening section gives the motivation for performance-based seismic design of bridges. The methodology section lays out the major steps of the design approach and addresses peer review for such projects. Seismic hazards and response analyses are covered, including upper-level and lower-level ground motions and site-specific hazard and site response analyses. Demand analysis guidance addresses the selection of analysis methods, from simplified and equivalent static procedures to nonlinear response history analysis, together with performance levels, hazard levels, and seismic design categories. The guidelines are intended for engineers designing bridges where enhanced seismic performance objectives are warranted.