Social psychological predictors of sleep hygiene behaviors in Australian and Hong Kong university students AbstractBackground. Sleep hygiene behaviors in undergraduate students are associated with night-time sleep duration and quality, fatigue, daytime sleepiness, and psychological distress. This study aimed to identify the social psychological factors that impact on university students' sleep hygiene behaviors in samples from two countries. Methods. Participants were undergraduate students from Australia (N=201) and Hong Kong (N=161). The study used a correlationalprospective design. Individuals self-reported their intention, attitude, subjective norms, perceived behavioral control, and past behavior with respect to sleep hygiene behaviors. Four weeks later, the students self-reported their action plans and participation in sleep hygiene behaviors. Results. Analysis indicated acceptable model fit to data for both the Australian and Hong Kong samples. Results showed significant direct effects of attitude, subjective norms, perceived behavioral control, and past behavior on intention, and significant direct effects of action planning and past behavior on prospectively measured sleep hygiene behavior. There were also significant indirect effects of attitude, subjective norms (Hong Kong sample only), and perceived behavioral control on behavior mediated by intention and action planning. Overall, the model predicted a large portion of the variance in sleep hygiene behavior for both the Australian (R 2 = .524) and Hong Kong (R 2 = .483) samples. Schenker and Gentleman t-tests found no parameters significantly differed between samples. Conclusions. Current results indicate that university students' sleep hygiene behaviors are a function of both motivational and volitional processes. This knowledge provides formative data to inform the development of behavior change interventions to improve the sleep hygiene practices of university students.