The internet and mobilisation of information and communication technologies (ICTs) have made non-manual work increasingly portable and remotely accessible. As a result, a considerable number of employees use their ICTs to engage in work-related tasks during designated non-work time, even without contractual obligation. However, existing research on such voluntary work-related ICT use remains fragmented and spread across disciplines. We conducted a narrative review of 56 studies to identify themes in existing research, synthesise the evidence base, as well as identify gaps in our understanding. We identify five themes, namely: (1) Social-normative organisational context, (2) Job-related characteristics and work processes, (3) Person characteristics, (4) Designated non-work time and well-being, and (5) Empowerment/Enslavement Paradox. A conceptual model of voluntary ICT use is developed by integrating the identified themes with existing organisational research, outlining the relationships between the identified themes and voluntary ICT use. In the discussion, we emphasise the need for more conceptual clarity on voluntary ICT use and related constructs, and for the integration of different disciplines and methodological approaches to advance knowledge in the field. We further identify person-centred research as critical future avenue to explore different ICT user types. Additionally, more research into the mechanisms and moderating influences regarding voluntary ICT use and its outcomes is considered advisable to advance our knowledge on the Empowerment/Enslavement Paradox and its potential resolution. We conclude with preliminary implications to inform practice, addressing the need for employers to provide control over voluntary ICT use, as well as employees enacting this control.