AimsTo explore the experience of registered nurses and their mentors in the implementation of the Gerontological Nursing Competencies in long‐term aged care and the perceived effectiveness and suitability of the programme to support nurse development.BackgroundThe global population is ageing and needs a reliable aged‐care nursing workforce.IntroductionOpportunities for education and mentorship for newly qualified and experienced aged‐care nurses warrant investigation.MethodsQualitative evaluation using semi‐structured focus groups was conducted following the implementation of the programme into five not‐for‐profit long‐term aged‐care organisations and analysed by a reflexive qualitative thematic approach and reported according to COREQ criteria.ResultsA total of 21 nurses (7 mentors and 14 mentees) participated in six focus groups. Five themes were generated: (1) nurses gained confidence and competence through the programme; (2) the facilitation of suitable mentoring activities and approaches was crucial to success; (3) the programme helps nurses recognise gerontology as a specialty; (4) the programme contributes to building a strategy of recruitment/retention/quality improvement in the sector; (5) barriers, challenges, changes and recommendations were identified.DiscussionThe Gerontological Nursing Competency model, which combined adaptive mentoring supported by reflective practice embedded in a gerontological nursing competencies framework, was perceived to improve nurse confidence and competence to lead and improve nursing standards of care.Conclusion and implications for nursing and health policyThe evidence‐based competencies are an acceptable and effective method for supporting gerontological nurse development. Expansion of, and accessibility to, the programme may aid global responses to aged‐care reform, by building the recognition of gerontological nursing as a specialty and contributing towards recruitment, retention and quality care improvements.