Background: A Living/Lived Experience Advisory Group (LEAG) was established as part of the update to the 2016 Clinical Practice Guidelines and Principles of Care for People with Dementia. The LEAG included eleven people, who were either living with dementia or were current or former carers of people living with dementia. Members supported evidence review and guideline development through participation in LEAG meetings and guideline development group meetings. The aim of this evaluation was to explore LEAG members’ perspectives about their experiences of engagement. Methods: Ten LEAG members participated in semi-structured interviews to share their experiences and perspectives of involvement in the LEAG. Researchers not previously involved in the guidelines conducted the interviews. Questions explored participants' thoughts on the pre-meeting information provided to them, how meetings were conducted, and the facilitation of meaningful engagement. Interviews were transcribed and analysed using Interpretative Phenomenological Analysis. Results: The results of this study indicated that LEAG members felt prepared and supported to contribute to meeting discussions in a meaningful way. Challenges were identified in managing a large number of members and ensuring each had an opportunity to contribute. Barriers to meaningful contribution included people arriving late to meetings, difficulty reading people’s body language in online meetings, and the need for people living with dementia to wait for their turn before contributing, which at times led to challenges in recalling what they wanted to share. Conclusions: The evaluation of involvement of the LEAG demonstrates that living and lived experience can meaningfully contribute to guideline development.