Objectives: To explore the experiences of informal caregivers of people with dementia with the hospitalization of their relative concerning patient care, interactions with nurses, caregivers’ situation and the acute hospital environment. Methods: Mixed‐methods design.MethodsThe data were collected using an online questionnaire among a panel of caregivers (n = 129), together with a focus group and individual interviews from February to November 2019. The data were triangulated and analysed using a conceptual framework. Results: Almost half of the respondents were satisfied with the extent to which nurses considered the patient's dementia. Activities to prevent challenging behaviours and provide person‐centred care were rarely seen by the caregivers. Caregivers experienced strain, intensified by a perceived lack of adequate communication and did not feel like partners in care; they also expressed concern about environmental safety. A key suggestion of caregivers was to create a special department for people with dementia, with specialized nurses. Conclusion: Positive experiences of caregivers are reported in relation to how nurses take dementia into account, involvement in care and shared decision making. Adverse experiences are described in relation to disease‐oriented care, ineffective communication and an unfamiliar environment. Caregivers expressed increased involvement when included in decisions and care when care was performed as described by the triangle of care model. Caregivers reported better care when a person‐centred approach was observed. Outcomes can be used in training to help nurses reflect and look for improvements. Impact: This study confirms that caregivers perceive that when they are more involved in care, this can contribute to improving the care of patients with dementia. The study is relevant for nurses to reflect on their own experiences and become aware of patients’ caregivers’ perspectives. It also provides insights to improve nurses’ training and for organizations to make the care and environment more dementia‐friendly.