Whilst, in many countries, the sudden enforced transfer to large-scale distance learning in state schools as a result of COVID_19 lockdown measures caused turmoil, it also provided an unprecedented opportunity to understand more about key factors associated with successful uptake of distance learning in the context of national education systems. Past research on distance-learning has often been limited to specific contexts and functions, but the widespread nature of the pandemic lockdown meant that for a period of time, a majority pupils in public education were following distance education programs. In this research, we build on previous models of e-learning accessibility to create a holistic model of core determinants of distance-learning uptake. In this model outcome variables include teacher estimations of the percentage of their pupils following online learning programs during a six-week period and teacher perceptions of online teaching success. Predictor variables include three core dimensions: contextual factors (school infrastructure, equipment, number of pupils being taught and the school itself), individual factors (teacher and pupil competence, autonomy and motivation to work with distance learning) and pedagogic factors (tools and teaching methods used). The model was tested within the context of the Swiss national lockdown starting on March, 13th 2020 and lasting two months. Data was collected in one Swiss canton. An online survey was issued to all teachers in state education for pupils in primary and secondary schools. 5,666 teachers participated and, in addition, forty-five teachers were interviewed using semi-directed interview techniques. Participation was voluntary. Results of regression analyses carried out on the survey data, controlling for school-level effects, and backed by qualitative data from interviews, revealed two key and inter-related findings. Firstly, we saw that a wide range of factors contributed to lower rates of pupil drop-out and higher levels of teacher perceived success. These included elements of all three core dimensions. Contextual factors (equipment, communication, pupils’ family-organization, the degree of psychological and practical support provided to teachers by their schools) played a role, as did individual factors (the competence, experience and motivation of teachers themselves and their pupils). Likewise pedagogic factors (choice of tools for distance teaching and methods used to organize learning) had significant relations with estimated pupil uptake and teacher perceptions of success in distance teaching. The second main finding revealed that, while certain pedagogic tools such as video-conferencing with cameras on and messaging had a positive main effect on pupil uptake, the success of other tools, such as online collaborative platforms was moderated by teacher motivation, having a positive effect on pupil uptake when associated with teacher beliefs in the importance of maintaining contact and providing feedback to their pupils. The first result points to the need for a coherent, coordinated approach to distance learning that takes into account the multitude of factors relating to school, pupils, teachers, tools and methods. The second result underlines the fact that it is not just the tools teachers use for distance teaching that matter, but their intention behind the use and the resulting way they use the tools that makes the difference. Keywords: Large-scale distance learning, holistic model, teacher motivation, pedagogic tools, pedagogic methods