Abstract Background Palliative care clinicians are regularly exposed to emotionally laden end-of-life care situations. Until now, the use of their emotions during palliative care consultations has remained understudied. We aimed to develop a theory to understand how palliative care clinicians use their emotions. Methods Qualitative data were collected via individual interviews held with different types of palliative care clinicians across the world (countries were selected based on their Quality of Death Index ranking). We used a social constructivist grounded theory approach to analyze the data using a constant comparative method. Results We held interviews with 21 palliative care clinicians (5 nurses, 11 physicians, 2 psychologists, and 3 social workers) from 10 different countries. Fourteen were female. Participants’ average age was 46 and they had 14 or more years of palliative care experience. The mean length of the interviews was 52 minutes. The process of using emotions could be characterized as follows: first, a difficult end-of-life encounter (e.g. ethical dilemmas or conflicts) would trigger a strong emotion in clinicians. Second, clinicians become aware of the specific emotion via its physical or psychological cues. Third, an assessment of the appropriateness of the use of the emotion follows, in which facilitators and barriers (e.g. the level of emotion skills, the view on emotions, or the feeling of safety in the team) interplay, influencing the clinician to act upon a specific emotion or not. Finally, with a specific intent (e.g. to build connection, stimulate patients and relatives to express their feelings, or clarify a point of view) the clinician shares, shows, or expresses the emotion. Conclusions We found that the strong emotions clinicians experience can be used as a valuable resource to provide palliative care. We also identified key steps to aid clinicians reflect on the appropriateness of using certain emotions in patient care. Key messages • Palliative care clinicians’ emotions can be considered as tools to support palliative care provision. • The developed theory shows potential to explore its applicability in other professions that are also regularly confronted with emotionally charged situations.