Smartphone use plays an increasingly important role in our daily lives. Philosophical research that has used first wave or second wave theories of extended cognition in order to understand our engagement with digital technologies has focused on the contribution of these technologies to the completion of specific cognitive tasks (e.g., remembering, reasoning, problem-solving, navigation).However, in a considerable number of cases, everyday smartphone use is task-unrelated. In psychological research, these cases have been captured by notions such as absent-minded smart-phone use (Marty-Dugas (...) et al., 2018) or smartphone-related inattentiveness (Liebherr et al., 2020).Given the prevalence of these cases, we develop a conceptual framework that can accommodate the functional and phenomenological characteristics of task-unrelated smartphone use. To this end, we will integrate research on second wave extended cognition with mind-wandering research and introduce the concept of ‘extended mind-wandering’. Elaborating the family resemblances approach to mind-wandering (Seli, Kane, Smallwood, et al., 2018), we will argue that task-unrelated smartphone use shares many characteristics with mind-wandering. We will suggest that an empirically informed conceptual analysis of cases of extended mind-wandering can enrich current work on digitally extended cognition by specifying the influence of the attention economy on our cognitive dynamics. (shrink)