diff --git a/pkg/action/action.go b/pkg/action/action.go
index 4ed718371..a36774033 100644
--- a/pkg/action/action.go
+++ b/pkg/action/action.go
@@ -33,6 +33,7 @@ import (
 	"text/template"
 	"time"
 
+	"go.yaml.in/yaml/v3"
 	"k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/cli-runtime/pkg/genericclioptions"
 	"k8s.io/client-go/discovery"
@@ -203,6 +204,12 @@ func annotateAndMerge(files map[string]string) (string, error) {
 			if strings.TrimSpace(doc) == "" {
 				continue
 			}
+			// kio.ParseAll flattens `kind: List` into one document per item; resolve aliases
+			// first so an anchor and its alias aren't split across documents (anchors are
+			// document-scoped), which would leave the alias dangling.
+			if resolved, rerr := resolveYAMLAliases(doc); rerr == nil {
+				doc = resolved
+			}
 			manifests, err := kio.ParseAll(doc)
 			if err != nil {
 				return "", fmt.Errorf("parsing %s: %w", fname, err)
@@ -223,6 +230,64 @@ func annotateAndMerge(files map[string]string) (string, error) {
 	return merged, nil
 }
 
+// resolveYAMLAliases materializes YAML aliases within a single document, leaving
+// documents that contain none unchanged.
+func resolveYAMLAliases(doc string) (string, error) {
+	var node yaml.Node
+	if err := yaml.Unmarshal([]byte(doc), &node); err != nil {
+		return "", err
+	}
+	if !resolveAliasNodes(&node) {
+		return doc, nil
+	}
+	stripAnchors(&node)
+	var buf bytes.Buffer
+	enc := yaml.NewEncoder(&buf)
+	enc.SetIndent(2)
+	if err := enc.Encode(&node); err != nil {
+		return "", err
+	}
+	_ = enc.Close()
+	return buf.String(), nil
+}
+
+// resolveAliasNodes replaces alias nodes with a deep copy of their anchor target,
+// returning true if any replacement was made.
+func resolveAliasNodes(n *yaml.Node) bool {
+	changed := false
+	for i, c := range n.Content {
+		if c.Kind == yaml.AliasNode && c.Alias != nil {
+			n.Content[i] = deepCopyClearAnchor(c.Alias)
+			changed = true
+			continue
+		}
+		if resolveAliasNodes(c) {
+			changed = true
+		}
+	}
+	return changed
+}
+
+// deepCopyClearAnchor returns a deep copy of n with anchors removed.
+func deepCopyClearAnchor(n *yaml.Node) *yaml.Node {
+	cp := *n
+	cp.Anchor = ""
+	cp.Alias = nil
+	cp.Content = make([]*yaml.Node, len(n.Content))
+	for i, c := range n.Content {
+		cp.Content[i] = deepCopyClearAnchor(c)
+	}
+	return &cp
+}
+
+// stripAnchors clears any remaining anchor names in the tree.
+func stripAnchors(n *yaml.Node) {
+	n.Anchor = ""
+	for _, c := range n.Content {
+		stripAnchors(c)
+	}
+}
+
 // splitAndDeannotate reconstructs individual files from a merged YAML stream,
 // removing filename annotations and grouping documents by their original filenames.
 // Documents without a filename annotation are assigned a synthesized name of the
diff --git a/pkg/action/action_test.go b/pkg/action/action_test.go
index 54b07273b..93393a96e 100644
--- a/pkg/action/action_test.go
+++ b/pkg/action/action_test.go
@@ -508,6 +508,70 @@ metadata:
     postrenderer.helm.sh/postrender-filename: 'templates/multi.yaml'
 data:
   key: value2
+`,
+		},
+		{
+			name: "kind List with anchor shared across items",
+			files: map[string]string{
+				"templates/list.yaml": `
+apiVersion: v1
+kind: List
+items:
+- apiVersion: v1
+  kind: ConfigMap
+  metadata:
+    name: cm-a
+  data: &shared
+    key: value
+- apiVersion: v1
+  kind: ConfigMap
+  metadata:
+    name: cm-b
+  data: *shared`,
+			},
+			expected: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cm-a
+  annotations:
+    postrenderer.helm.sh/postrender-filename: 'templates/list.yaml'
+data:
+  key: value
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cm-b
+  annotations:
+    postrenderer.helm.sh/postrender-filename: 'templates/list.yaml'
+data:
+  key: value
+`,
+		},
+		{
+			name: "anchor and alias within a single manifest",
+			files: map[string]string{
+				"templates/cm.yaml": `
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cm
+data:
+  defaults: &d
+    a: "1"
+  prod: *d`,
+			},
+			expected: `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cm
+  annotations:
+    postrenderer.helm.sh/postrender-filename: 'templates/cm.yaml'
+data:
+  defaults:
+    a: "1"
+  prod:
+    a: "1"
 `,
 		},
 		{