Abstract: To maximize the delivery and efficacy of acceptance and commitment therapy (ACT), there is a need to better understand the lived experiences of individuals undergoing ACT-based interventions. This can be helpful to determine what was perceived as effective and examine shifts in perspectives that influence daily functioning. The current study examined qualitative feedback among 21 U.S. Veterans (Mage = 57.43, SD = 12.94) with chronic pain one month after completing the Acting with Mindfulness for Pain (AMP) protocol, an 8-week, group-delivered ACT intervention that integrates formal mindfulness meditation practice as a principal treatment component. We analyzed responses to semi-structured interviews performed at 1-month post-treatment using an inductive thematic approach and found four overarching themes: Shift in Internal State, Engaging in Life, Symptom Relief, and Group Dynamics. The Shift in Internal State and Engaging in Life themes and sub-themes reflected important elements of psychological flexibility as defined within ACT, including pain acceptance, change in the experience of thoughts and emotions, improvement in daily functioning and movement towards personal values. The Symptom Relief theme was primarily supported by descriptions of the utility of mindfulness meditation for pain and stress relief. The Group Dynamics theme highlighted the importance of member-member and member-facilitator relationships. These data provide insights into the lived experiences of Veterans undergoing the AMP protocol and provide support for future research examining the efficacy of AMP. While theoretically consistent themes were identified, the Symptom Relief theme provides important considerations on the inclusion of mindfulness meditation within ACT-based approaches.