Background <p>Despite its recognized importance in dementia care, advance care planning is frequently postponed. Understanding factors that support and hinder readiness (i.e., an individual’s willingness and ability to engage in advance care planning discussions) is essential, to ensure that people with dementia and their family caregivers can participate effectively in planning for future care. This study aimed to identify factors influencing readiness from the perspectives of people with dementia, family caregivers, and healthcare professionals.</p> Methods <p>Semi-structured qualitative interviews were conducted with people with dementia, family caregivers, and healthcare professionals across multiple care settings in the Netherlands. Inductive qualitative content analysis was used to identify key factors influencing readiness.</p> Results <p>For people with dementia (<i>n</i> = 6), readiness was facilitated by a desire for autonomy. Readiness was hindered by focusing on the present, surrendering to a perceived lack of control over the future, avoiding sensitive topics, and relying on healthcare professionals to initiate discussions. For both people with dementia and family caregivers (<i>n</i> = 5 family caregivers), readiness was facilitated by a desire to prepare for the future, and hindered by the complexity of advance care planning. (Lack of) collaboration and social support, previous personal experiences, and the relationship with the healthcare professional either facilitated or hindered readiness. No distinct factors were identified solely for family caregivers. Healthcare professionals (<i>n</i> = 13) reported factors related to individual healthcare professionals: difficulty addressing sensitive topics as hindering readiness for advance care planning, while (lack of) personal priority, (limited) education and training, and (lack of) experience either facilitated or hindered it. They also reported factors related to healthcare organizations: interprofessional cooperation and communication facilitated readiness, while (lack of) implementation leadership, (limited) time to implement advance care planning, and (limited) procedural support either facilitated or hindered readiness.</p> Conclusions <p>Readiness for advance care planning in dementia is dynamic and shaped by personal, relational, and systemic factors. Addressing these factors may facilitate timely and meaningful implementation of advance care planning, ensuring future care aligns with the values and preferences of people with dementia and their families.</p>