Volumes are managed storage outside the container's writable layer that persist across container restarts and can be shared between containers.

Three storage options: named volumes (Docker-managed, best for production data), bind mounts (host directory mapped into container, good for development), tmpfs mounts (in-memory, ephemeral). Use volumes for databases, log files, and any data that must survive a container restart. In Kubernetes, this maps to PersistentVolumes and PersistentVolumeClaims.