OBJECTIVES: Informal caregiver burden is not formally or routinely considered in health technology assessment (HTAs). However, the burden of many diseases on informal caregivers’ quality of life has been recognized, including hematological cancers. This study aimed to understand the role of informal caregiver burden in HTA in France, Germany, and the US, using the example of multiple myeloma (MM). METHODS: Telephone interviews lasting approximately 1 hour were conducted with two HTA experts from each country, based on an interview guide. Interviews were recorded and common themes identified from assessment of the narrative. RESULTS: The French advisors considered that the cost savings realized through informal care compared with formal caregiving are neglected, and that data on informal caregiver burden should be incorporated into cost-effectiveness models where available. The German advisors suggested that caregiver burden may be recognized in HTA if it can be related to patient benefit. Discussions in this area are increasing but changes to the acceptability of caregiver burden data was mostly likely to occur elsewhere in the healthcare system (i.e., outside of the benefit assessment process). Advisors in the US reported that payers’ views of caregiver burden are changing and that this information should be considered as more patients involve their caregivers in decision-making, or caregivers make the decisions (for some groups of patients). CONCLUSIONS: Informal caregiver burden data are not currently considered important in HTA in Europe or the US, although there are suggestions that this may change. Even where such data have been included in HTA submissions, they have not generally been a driver of HTA decision-making.