A comprehensive deep dive into implementing Zero Trust security architecture on Google Kubernetes Engine (GKE), emphasizing a fundamental shift from traditional perimeter-based security to a model where trust is never assumed and every interaction must be explicitly verified. By centering the discussion on the core pillars of Zero Trust—verifying explicitly, enforcing least privilege, and assuming breach—the presentation demonstrated how to leverage Google Cloud-native tools such as Workload Identity for strong authentication, Binary Authorization for supply chain integrity, and mTLS for secure service-to-service communication. This approach ensures that security is deeply integrated into the infrastructure, providing a robust defense against modern threats by continuously validating every request and minimizing the potential impact of any security incident within the Kubernetes environment.