Background: People with dementia are confronted with negative consequences due to hospital stays. When developing new interventions to improve care for people with dementia in acute care hospitals (by intervention we understand organisational strategies, programmes, and/or treatments and actions performed by healthcare professionals), it is crucial to have a comprehensive overview of previous interventions tested in this field and to know the outcomes.Methods: We conducted a systematic review to provide an overview of interventions targeting the care situation of patients with dementia in acute care hospitals. We included trials with interventional study designs and systematic reviews without restrictions regarding the outcomes. We searched five electronic databases, conducted a hand search of journals and performed forward and backward citation tracking of included studies. For risk of bias assessment, we used the Cochrane Collaboration’s tool for assessing risk of bias in randomised trials, ROBANS (for non-randomised controlled trials) and AMSTAR (for systematic reviews). We provide tabular and narrative summaries of the findings. Results: Twenty studies met the inclusion criteria. The findings indicated a broad range of interventions and outcomes. We categorised the interventions into eight intervention types: educational programmes, special non-pharmacological interventions, delirium management programmes, inpatient rehabilitation interventions, family-/person-centred programmes, use of specially trained nurses, volunteer programmes and special care units. Staff outcomes were investigated in most of the studies, followed by patient outcomes. Outcomes concerning relatives were reported in four studies. Educational programmes were the most commonly reported intervention type and resulted in improved staff outcomes. Family-/person-centred care programmes, use of specially trained nurses and delirium management programmes were effective in improving patient-related outcomes, e.g. delirium severity and functional performance. Rehabilitation interventions after hip fractures and special care units for people with dementia hardly showed any significant effects. Conclusions: Although the included interventional studies reported improved outcomes concerning patients, relatives and staff, the evidence is insufficient to declare which interventions are effective in improving care for people with dementia in acute care hospitals. Future research should focus on relevant patient and family caregiver outcomes. Thereby, it is necessary to consider the complexity of the interventions. Interventions addressing relatives, interprofessional collaboration and the entire practice culture are needed. Trial registration: PROSPERO: CRD42018111032.