This study aimed to evaluate and provide recommendations to improve the effectiveness of an age inclusive compassion-focused therapy (CFT) group in secondary mental health services for participants experiencing a range of mental health difficulties. Of particular interest was the acceptability and impact of having a wide range of ages in such a group. The study employed a mixed method design. Validated self-report questionnaires were administered before and after the group intervention, and qualitative semi-structured interviews were conducted with six group participants. There was a significant increase in ratings on the Self-Compassion Scale (SCS) and Mindful Attention Awareness Scale (MAAS), a significant decrease in the depression subscale within the Depression and Anxiety Stress Scale (DASS) and a significant reduction in the risk subscale of the Clinical Outcome in Routine Evaluation (CORE). No significant differences were found on the overall scores and other subscales of the CORE and the DASS. Thematic analysis of the qualitative data identified four main themes: “Connection with others”, “Experience of a diverse age range”, “Group as a secure space” and “New strategies and tools”. This study provides preliminary evidence that an age inclusive CFT group is well received and has a beneficial impact for participants, with particular positivity gained through compassionately connecting with others. The range of ages was appreciated and appeared to have therapeutic benefits, although awareness of differing age-related needs is important. Limitations, recommendations for improvement and future research are discussed.