Background: UK care home residents are prescribed an average of 8-10 medicines daily with evidence that inappropriate prescribing is prevalent leading to problematic polypharmacy. This increases the risk of adverse drug events that negatively affect resident outcomes, quality-of-life and have financial costs to the NHS. Deprescribing (the cessation of inappropriate medicines) can reduce inappropriate prescribing, however, there are significant barriers to its implementation in this setting. Identifying and understanding barriers and facilitators of stopping inappropriate medicines is necessary to improve the implementation of deprescribing in care homes. Methods: A literature review was conducted to synthesise existing evidence. Semi-structured interviews were conducted with residents, relatives, care home staff, GPs and pharmacists. Themes and explanations were developed using Framework Analysis. Theoretical models of behaviour change were applied to identify candidate components for a novel intervention for deprescribing in care homes. Findings: The literature review highlighted a lack of evidence regarding residents’ and relatives’ attitudes to deprescribing, and a lack of depth regarding barriers and facilitators to deprescribing. Three themes were identified from the empirical data: 1) individuals involved in the deprescribing process; 2) social barriers; 3) logistical barriers. Theme 1 highlighted the complexity of the deprescribing process and themes 2&3 identified and explained systematic barriers and facilitators to deprescribing. Social barriers included a reluctance to discuss life expectancy and healthcare professionals’ perceptions of residents and relatives. Logistical barriers included the unavailability of key stakeholders and navigating health and social care systems. Potential intervention components included; demonstrating the behaviour of deprescribing, providing feedback on its outcomes plus provision of prompts. Conclusions: This thesis has provided novel, in-depth explanation and insight of the barriers and facilitators to deprescribing from the perspective of key stakeholders. This was utilised to identify potential components of a deprescribing behaviour change intervention for implementation and evaluation in care homes.