Acceptance and Commitment Therapy (ACT) stands as a proven psychotherapeutic approach, demonstrating efficacy in enhancing outcomes like mood and quality of life among individuals grappling with anxiety, depression, and chronic pain. This study seeks to ascertain the clinical and cost-effectiveness of iACT4CARERS, in addition to treatment as usual, in comparison to solely receiving treatment as usual among family carers of individuals with dementia exhibiting symptoms of anxiety over a span of 12 weeks. Participants will receive support from a trial therapist across 8 sessions.