CPD Accredited Diploma · Self-Paced Online
Diploma in Acceptance & Commitment Therapy
Study the psychology of a values-driven life with Dr John Crimmins and discover how Acceptance and Commitment Therapy can support meaningful, lasting change.
What Is ACT?
ACT, explained
ACT is a third-wave cognitive behavioural approach developed by Steven Hayes and colleagues.
- Not about eliminating difficult thoughts and feelings — ACT works on the principle that struggling against them often causes more suffering than the thoughts and feelings themselves.
- Built around psychological flexibility — staying present, making room for difficult internal experience, and still taking action guided by what genuinely matters.
- One of the most widely used third-wave approaches, alongside CBT and DBT.
- Strong evidence base across anxiety, depression, and chronic pain.
Develop Psychological Flexibility
Master the practice of helping people move towards Positive Change
ACT offers a compassionate, evidence-based way of working with difficult thoughts and feelings while supporting action guided by personal values.
Help people live fully
Learn the central ACT processes, including acceptance, defusion and values-guided action.
Understand avoidance
Explore how experiential avoidance and rigid thinking sustain distress, and how ACT responds.
Study third-wave CBT
Understand psychological flexibility, contextual behavioural science and the evidence behind ACT.
Learn with Dr John Crimmins
Experienced teaching with personal tutorial support
Dr John Crimmins, founder of The Behaviour Institute, brings more than 25 years of clinical experience to your learning.
- Expert-led curriculum: course material developed and guided by Dr Crimmins.
- Applied understanding: connect ACT theory with clinical and professional contexts.
- Personal support: receive individual guidance and feedback on your assignments.
- CPD certification: study with a provider approved by the CPD Certification Service, London.
Six Structured Units
Course content
Move from the foundations of ACT through its six core processes, case formulation and integration into professional work.
What is ACT?
The origins of ACT within third-wave CBT, the psychological flexibility model and why working with difficult experiences can be more helpful than fighting them.
Acceptance & Defusion
Relating differently to unwanted thoughts and feelings, unhooking from unhelpful thinking and using core defusion methods.
Present-Moment Awareness
Mindfulness within ACT, present-moment contact and helping people access a stable sense of self beneath thoughts and stories.
Values & Committed Action
Clarifying what genuinely matters and translating values into sustained, workable behaviour change rather than vague intentions.
ACT Case Formulation
Building an ACT case conceptualisation and applying the model across anxiety, depression, chronic pain and other presentations.
Integrating ACT into Practice
Using the therapeutic relationship as part of the ACT process and integrating the approach into existing professional work.
Open to Beginners and Professionals
Who is this course for?
No previous training in CBT or DBT is required. The programme is designed for people who want a structured understanding of ACT and psychological flexibility.
- Mental health professionals: deepen your understanding of acceptance, values and behaviour change.
- Counsellors and psychotherapists: add an evidence-based third-wave approach to your existing work.
- Coaches, educators and support workers: develop psychologically informed ways of helping people move towards meaningful goals.
- Personal development: explore how ACT principles can support greater flexibility and values-driven living.
Join a global learning community of more than 5,000 students.
Recognised Professional Development
CPD certified in London
The Behaviour Institute is an approved training provider with the CPD Certification Service in London, United Kingdom. The programme provides structured professional development and a diploma upon successful completion.
START YOUR ACT DIPLOMA TODAY
Enrol and receive immediate course access
Study at your own pace with lifetime access to the learning materials and personal tutorial support throughout the programme.
£395 one-time payment · or four payments of £99 (contact us for details of subscription)
Your official diploma is included following successful completion. There are no hidden or recurring fees.
Enrol NowStudent Experiences
Learning supported by expertise and encouragement
I signed up for a five-diploma package and extracted valuable tools from every course. The mix of video, literature, research and case studies creates an excellent learning environment. Dr Crimmins' detailed feedback and continuous support are invaluable.
The course content is extremely valuable—academically rich while remaining relevant to everyday life. Additional reading was provided for deeper research, and the support and encouragement throughout my studies made the experience positive and exciting.
The course material was interesting, accessible and easy to navigate. The email support made it an excellent learning journey. The programme opened a new path in my professional career and will benefit our community in the UAE.
