Integrating social exchange and information processing theories, this study examines the influence of high-performance human resource (HR) practices on service-oriented organizational citizenship behavior OCB) through two climates—justice climate and service climate. This field study of 1133 customer contact employees and 119 human resource managers from 119 hotels in Taiwan has shown that social climates of justice and service mediate the influence of high-performance HR practices on serviceoriented OCB. The study demonstrates that high-performance HR practices affect employees’ cognition on how they are treated by hotels and what service behaviors are expected, which in turn can positively influence collective service-oriented OCB