A high-pressure jet-stirred reactor (JSR) was designed and fabricated in order to understand and characterize chemical kinetics with respect to gas-phase chemistry relevant to combustion and atmospheric pollution. The JSR is constructed of fused quartz and utilizes four 1-mm diameter mixing jets to induce turbulent mixing and ensure homogeneity inside the 30 cm3 reaction volume. The spherical reactor was designed to operate at a maximum pressure of 50 atm, maximum temperature of 1200 K, and minimum residence time of 30 ms. The heating elements of the reactor are comprised of four twin-core heating elements vacuum-brazed onto the surface of Inconel cylinders surrounding the reaction volume and a pre-heating region. The pressure vessel containing the reactor is made of 1.75 thick stainless steel. High pressures are achieved by means of pressure-balancing inside and outside the quartz tube. Sonic probe sampling is used to extract and store gaseous samples for tandem absorption spectroscopy and mass spectrometry analysis.