In research universities, research time is often too scarce to satiate the wishes of all faculty and must be allocated according to guidelines and principles. We examine self-reported research hours for full-time faculty at research universities in 13 countries (Argentina, Australia, Brazil, Canada, China, Finland, Germany, Italy, Malaysia, Norway, UK, USA, and Hong Kong, a semi-autonomous special administrative region of China). We examine the level of variation in individual faculty research time and the factors associated with individual differences, including differences in: (a) university policy regarding the allocation of working time for research between individual faculty members, (b) individual motivation towards research, and (c) family commitments. Our results suggest that the factors associated with additional research time vary across countries, but individual motivation towards research (relative to teaching) is a significant in all countries. University policies towards research and the research status of individual faculty, are relatively weak predictors of individual research time, though stronger effects are generally found in English-speaking countries. Research hours typically decrease with age, but plateau or increase in the oldest cohorts. Family and gender are weak predictors of research time amongst full-time faculty.