The mass migration to online learning during the COVID-19 pandemic has increased students' burden of self-regulating their learning. Amid this change, students with low self-efficacy may struggle due to their tendency to exhibit poor self-regulated learning and course outcomes. This study investigated the potential buffering role of students' curiosity in the impact of self-efficacy on self-regulated learning and course outcomes. Three surveys were administered to 363 undergraduates enrolled in online courses across a semester. Both self-efficacy and curiosity directly predicted self-regulated learning and course outcomes. The interaction between the two had significant effects on help-seeking and course grade. Students were less likely to seek help in online courses when either their efficacy or curiosity was low. High curiosity mitigated the negative effects of low self-efficacy on course grades. Students' self-regulated learning mediated the link between motivation and course outcomes. These findings have implications for supporting students' success in remote learning.