Background: Paramedics are increasingly being called to attend patients dying from advanced incurable conditions. However, confidence to deal with such calls varies, with many feeling relatively unskilled in this aspect of their role. A number of interventions have been piloted to improve their skills in end-of-life care (EoLC) but without a fully specified theoretical model. Theory of Change models can provide theoretical and testable links from intervention activities to proposed long-term outcomes and indicate the areas for assessment of effectiveness. This study aimed to develop an intervention for improving paramedic EoLC for patients in the community. Methods: A Theory of Change approach was used as the overarching theoretical framework for developing an intervention to improve paramedic end-of-life skills. Nine stakeholders - including specialist community paramedics, ambulance call handlers and palliative care specialists - were recruited to five consecutive online workshops, ranging between 60 and 90 min. Each workshop had 2–3 facilitators. Over multiple workshops, stakeholders decided on the desired impact, short- and long-term outcomes, and possible interventions. During and between these workshops a Theory of Change model was created, with the components shared with stakeholders. Results: The stakeholders agreed the desired impact was to provide consistent, holistic, patient-centred, and effective EoLC. Four potential long-term outcomes were suggested: (1) increased use of anticipatory and regular end-of-life medications; (2) reduced end-of-life clinical and medication errors; (3) reduced unnecessary hospitalisations; (4) increased concordance between patient preferred and actual place of death. Key interventions focused on providing immediate information on what to do in such situations including: appraising the situation, developing an algorithm for a treatment plan (including whether or not to convey to hospital) and how to identify ongoing support in the community. Conclusions: A Theory of Change approach was effective at identifying impact, outcomes, and the important features of an end-of-life intervention for paramedics. This study identified the need for paramedics to have immediate access to information and resources to support EoLC, which the workshop stakeholders are now seeking to develop as an intervention.