Can mobile-assisted language learning (MALL) foster self-directed learning outside the classroom? This article examines informal, out-of-class engagement with a MALL tool: Duolingo. After being invited to use Duolingo, 118 higher education language students agreed to have their activity in the application tracked. In addition to the data collected from the Duolingo dashboard, questionnaires, as well as semi-structured interviews, were implemented. Results viewed from Garrison’s dimensions of self-directed learning (motivation, self-management and self-monitoring) reveal inconsistencies between what students think about the app and what they do with it. Questionnaires suggest that Duolingo can encourage out-of-class learning through fun activities, but interviews reveal a lack of sustained motivation, self-monitoring and self-management reflected in the low usage of the application. Tracking data reveals that students lack the time for out-of-class MALL during course weeks and are more active during holidays. The results highlight the importance of a context in which users are encouraged to take responsibility for their learning. However, most students will, besides encouragement, also need training and support for their self-directed learning.