diff --git a/tensorflow_privacy/privacy/privacy_tests/membership_inference_attack/data_structures.py b/tensorflow_privacy/privacy/privacy_tests/membership_inference_attack/data_structures.py
index a12cf42a..76bbd941 100644
--- a/tensorflow_privacy/privacy/privacy_tests/membership_inference_attack/data_structures.py
+++ b/tensorflow_privacy/privacy/privacy_tests/membership_inference_attack/data_structures.py
@@ -316,6 +316,21 @@ class AttackInputData:
   # treated as multilabel data.
   force_multilabel_data: bool = False
 
+  # Directly comparing members of the type `np.ndarray` can throw an error:
+  # "The truth value of an array with more than one element is ambiguous."
+  # So we bring back an explicit implementation of __eq__ like it was prior to
+  # Python 3.13 in order work around this possibility.
+  def __eq__(self, other):
+    if self is other:
+      return True
+    if other.__class__ is self.__class__:
+      return tuple(
+          getattr(self, field.name) for field in dataclasses.fields(self)
+      ) == tuple(
+          getattr(other, field.name) for field in dataclasses.fields(other)
+      )
+    return NotImplemented
+
   @property
   def num_classes(self):
     if self.labels_train is None or self.labels_test is None: