Aim To examine whether the impact of mistreatment by patients on nurses’ burnout can be exacerbated or attenuated depending on emotion‐regulation strategies, and to explore the moderating role of supervisor support in the relationship between mistreatment and deep acting. Background Aggression from patients is known to contribute significantly to nurse burnout. To date, the moderating role of emotion regulation strategies in the mistreatment–outcomes relationship has seldom been considered. Methods The sample consisted of 105 nurses who were working while studying for their Master's degree. Data were collected using self‐reported questionnaires. The research hypotheses were tested using hierarchical regression analyses. Results Mistreatment and surface acting significantly contributed to nurse burnout. Deep acting had a buffering effect on the relationship between mistreatment and depersonalisation. The results also indicate that supervisor support was negatively associated with surface acting and may increase deep acting in response to mistreatment. Conclusion The use of an effective strategy for regulating emotions and supervisor support can protect nurses from the depletion of emotional resources. Implications for nursing management By introducing emotion‐regulation skills training and by encouraging the availability of support from supervisors, health‐care organisations can help nurses better cope with emotionally charged interactions.