diff --git a/docs/changelog/136508.yaml b/docs/changelog/136508.yaml
new file mode 100644
index 0000000000000..6cdad9fa50fdd
--- /dev/null
+++ b/docs/changelog/136508.yaml
@@ -0,0 +1,6 @@
+pr: 136508
+summary: Associate legacy audit index
+area: Transform
+type: bug
+issues:
+ - 121241
diff --git a/muted-tests.yml b/muted-tests.yml
index 256ba3eef305e..1309b0c06e93d 100644
--- a/muted-tests.yml
+++ b/muted-tests.yml
@@ -317,9 +317,6 @@ tests:
     issue: https://github.com/elastic/elasticsearch/issues/121117
   - class: org.elasticsearch.xpack.ml.integration.PyTorchModelIT
     issue: https://github.com/elastic/elasticsearch/issues/121165
-  - class: org.elasticsearch.xpack.transform.integration.TransformAuditorIT
-    method: testAuditorWritesAudits
-    issue: https://github.com/elastic/elasticsearch/issues/121241
   - class: org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT
     method: test {p0=nodes.stats/11_indices_metrics/indices mappings exact count test for indices level}
     issue: https://github.com/elastic/elasticsearch/issues/120950
diff --git a/x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/Transform.java b/x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/Transform.java
index 7f4b9543698b4..e473c94c91b0e 100644
--- a/x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/Transform.java
+++ b/x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/Transform.java
@@ -128,6 +128,7 @@
 import static org.elasticsearch.xpack.core.ClientHelper.TRANSFORM_ORIGIN;
 import static org.elasticsearch.xpack.core.transform.TransformMessages.FAILED_TO_UNSET_RESET_MODE;
 import static org.elasticsearch.xpack.core.transform.transforms.persistence.TransformInternalIndexConstants.AUDIT_INDEX_PATTERN;
+import static org.elasticsearch.xpack.core.transform.transforms.persistence.TransformInternalIndexConstants.AUDIT_INDEX_PATTERN_DEPRECATED;
 import static org.elasticsearch.xpack.core.transform.transforms.persistence.TransformInternalIndexConstants.TRANSFORM_PREFIX;
 import static org.elasticsearch.xpack.core.transform.transforms.persistence.TransformInternalIndexConstants.TRANSFORM_PREFIX_DEPRECATED;
 
@@ -436,7 +437,10 @@ public Collection<SystemIndexDescriptor> getSystemIndexDescriptors(Settings sett
 
     @Override
     public Collection<AssociatedIndexDescriptor> getAssociatedIndexDescriptors() {
-        return List.of(new AssociatedIndexDescriptor(AUDIT_INDEX_PATTERN, "Audit index"));
+        return List.of(
+            new AssociatedIndexDescriptor(AUDIT_INDEX_PATTERN, "Audit index"),
+            new AssociatedIndexDescriptor(AUDIT_INDEX_PATTERN_DEPRECATED, "Legacy audit index")
+        );
     }
 
     @Override