This work demonstrates high-performance BN/β-Ga2O3 metal-insulator-semiconductor Schottky barrier diodes (MIS SBDs). The BN layer is directly grown on the β-Ga2O3 by pulsed laser deposition (PLD). The presence of a ~2.8 nm BN layer is confirmed by a series of techniques, including X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM). The MIS SBDs show an on/off ratio of ~ 107 and an increased on-resistance due to the insertion of the BN layer. An increased Schottky barrier height is observed from capacitance-voltage (C-V) measurements. Temperature-dependent measurements suggest the existence of an inhomogeneous Schottky barrier. The breakdown voltage is enhanced from 732 V for a regular SBD to 1045 V for a MIS SBD with the ultrathin BN layer, which can be ascribed to the increased Schottky barrier height and reduced leakage currents. This work provides a promising way to optimize the performance of β-Ga2O3-based devices for power electronics.