Targeted efforts to better understand the barriers and facilitators of stakeholders and healthcare settings to implementation of exercise and education self-management programmes for osteoarthritis (OA) are needed. This study aimed to explore the barriers and facilitators to the implementation of Good Life with osteoArthritis in Denmark (GLA:D), a supervised group guideline-based OA programme, across Irish public and private healthcare settings. Interviews with 10 physiotherapists (PTs; 8 public) and 9 people with hip and knee OA (PwOA; 4 public) were coded by the Consolidated Framework for Implementation Research (CFIR) constructs in a case memo (summary, rationale, quotes). The strong positive/negative implementation determinants were identified collaboratively by rating the valence and strength of CFIR constructs on implementation. Across public and private settings, PTs and PwOA strongly perceived GLA:D Ireland as evidence-based, with easily accessible education and modifiable marketing/training materials that meet participants’ needs, improve skills/confidence and address exercise beliefs/expectations. Despite difficulties in scheduling sessions (e.g., work/caring responsibilities), PTs in public and private settings perceived advantages to implementation over current clinical practice (e.g., shortens waiting lists). Only PTs in public settings reported limited availability of internal/external funding, inappropriate space, marketing/training tools, and inadequate staffing. Across public and private settings, PwOA reported adaptability, appropriate space/equipment and coaching/supervision, autonomy, and social support as facilitators. Flexible training and tailored education for stakeholders and healthcare settings on guideline-based OA management may promote implementation. Additional support on organising (e.g., scheduling clinical time), planning (e.g., securing appropriate space, marketing/training tools), and funding (e.g., accessing dedicated internal/external grants) may strengthen implementation across public settings.