In recent years, the use of Ultra-High Performance Concrete (UHPC) in bridge construction has been growing significantly. UHPC is considered an ideal material for bridge connections due to its excellent early-age mechanical properties, exceptional durability, and high workability. The objective of this paper is to evaluate the interface shear resistance of UHPC as it is considered a key property in the performance of connections between precast concrete deck panels and bridge girders. Interface shear resistance is evaluated experimentally for a commercial UHPC through two laboratory testing methods. Direct shear test is conducted to evaluate interface shear resistance of monolithic UHPC. Slant shear test is conducted to evaluate interface shear resistance of UHPC cast against hardened conventional concrete with three surface textures: smooth, shallow grooved, and deep grooved. Test results are compared to those predicted using the models obtained from literature and bridge design specifications.