Microservices architectures have made applications highly scalable and maintainable, but they have also multiplied the number of entry points and attack surfaces. Zero Trust principles address this by treating every service‑to‑service call as untrusted, regardless of where it originates. In cloud‑native environments, this means authenticating and encrypting all traffic with mutual TLS, enforced by a service mesh such as Istio, Linkerd, or Consul. Fine‑grained authorization policies restrict which identities can consume each API, while least‑privilege network policies limit lateral movement between namespaces and clusters. Continuous verification of identity and device posture at the edge of the mesh, combined with observability across traces and logs, allows teams to detect and respond to anomalies quickly. By embedding Zero Trust directly into microservices security, organizations protect dynamic workloads without hindering agility.