Out-of-class study time is essential in students' language learning, but few studies in ELT measure out-of-class study time or investigate how teachers can encourage, rather than demand it. In Japan, out-of-class study time is lower than might be expected, ranging from zero to an hour per week. This study therefore sets out to establish those factors that can increase out-of-class study time without extrinsic motivators such as homework and testing. Results from self-reports and course evaluations suggest that (1) clear course aims, (2) strong student-teacher relationships, (3) non-threatening classroom environments, and (4) interactive classroom procedures boost out-of-class study time. Finally, we hope this study will become a catalyst for more in-depth discussion of how to facilitate more productive out-of-class study time, and ultimately students' attainment of higher proficiency in the target language.