Observational tools can support the understanding of the complex needs of older people with dementia and aid delivery of person-centred care. However, existing tools are complex and resource intensive to use. To develop and evaluate the acceptability and feasibility of a low-resource, observational tool to support staff reflection and practice development. Intervention development of the Person-Centred Observation and Reflection Tool (PORT) and acceptability and feasibility study, using surveys and focus groups in the UK, Norway and Spain. PORT was reported as easy, accessible and acceptable to use. The observation was identified as powerful for individual staff development and provided an evidence-based source for underpinning individualised care planning. Potential time challenges associated with implementation were identified. Initial evaluation indicates PORT is an acceptable and feasible tool for use in health and social care settings for older people. Further research is needed on implementation models and the impacts of PORT use. PORT may be a useful tool to support individual staff development in care settings and person-centred care planning for people with dementia.