Dr. John Theis

Clinical Psychologist | Certified Relationship & Family Therapist

John brings a rich and multifaceted background to his clinical work. He began his adulthood as a priest, did an M.Sc. in Chemistry and was Principal of St. Jerome’s High School in Kitchener-Waterloo. After leaving the clergy he was a professor at the University of Waterloo in Psychology for 26 years before taking early retirement to work in full-time private practice. This diverse life experience shapes his approach to therapy.

Much of Dr. Theis’ training in family therapy was done over many years in Italy. He remains a wannabe Italian.

Therapeutic Style

Dr. Theis is calm, insightful and untroubled by complexity and chaos, especially in families. He anchors people with kindness and solidity during life's storms.

He values treating each client as unique and tailoring the therapeutic approach to their needs.

Modalities & Areas of Focus

Dr. Theis draws from several approaches:

  • Humanistic & Existential Therapy

  • Family Systems

  • Cognitive Behavioural Therapy

  • Interpersonal Therapy

  • Integrative & Client-Centered

He works with adult individuals, couples and families experiencing

  • Relationship issues

  • Anxiety

  • Depression

  • Life transitions

  • Fathers and sons

  • Personal growth/reflection

  • Grief and aging

  • Clinical supervision and consultation

Working with Dr. Theis

Dr. Theis offers virtual therapy sessions for adult individual, couples and families. He does not offer free consultations but encourages prospective clients to review therapist profiles and reach out with any questions prior to booking.

Background & Experience

  • Clinical Psychologist in Ontario

  • Certified in Relationship and Family Therapy

  • University professor in Psychology (retired in 1996)

  • In private practice since 1996

  • Based in Guelph since 2003

Contact Dr. Theis

Phone: 519-836-1277

Virtual sessions available | Now accepting clients

We're Here When You're Ready

Whether you're seeking treatment, clarity, support, or simply a space to talk, we're here to help. Reach out today to connect with a therapist and take the next step in your journey.

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