diff --git a/CHANGELOG.md b/CHANGELOG.md
index 91eb9c8f3..b15d4facf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ## Unreleased
 
 ### Changes
+
+- [UUM-138539] Removed the pb_ObjectArray file that was deprecated 8 years ago and is not used amymore.
 - [UUM-138960] Removed a large utility dictionary to reduce binary size and runtime memory overhead. 
 
 ### Fixed
diff --git a/Editor/EditorCore/MaterialEditor.cs b/Editor/EditorCore/MaterialEditor.cs
index 4729d4b2c..55855e28e 100644
--- a/Editor/EditorCore/MaterialEditor.cs
+++ b/Editor/EditorCore/MaterialEditor.cs
@@ -173,24 +173,8 @@ public static MaterialPalette CurrentPalette
                     if (s_CurrentPalette != null)
                         return s_CurrentPalette;
 
-                    // If no existing pb_MaterialPalette objects in project:
-                    // - create a new one
-                    // - check for the older pb_ObjectArray and copy data to new default
+                    // If no existing pb_MaterialPalette objects in project create a new one
                     s_CurrentPalette = FileUtility.LoadRequired<MaterialPalette>(s_MaterialPalettePath);
-
-                    string[] m_LegacyMaterialArrays = AssetDatabase.FindAssets("t:pb_ObjectArray");
-
-                    for (int i = 0; m_LegacyMaterialArrays != null && i < m_LegacyMaterialArrays.Length; i++)
-                    {
-                        pb_ObjectArray poa = AssetDatabase.LoadAssetAtPath<pb_ObjectArray>(AssetDatabase.GUIDToAssetPath(m_LegacyMaterialArrays[i]));
-
-                        // Make sure there's actually something worth copying
-                        if (poa != null && poa.array != null && poa.array.Any(x => x != null && x is Material))
-                        {
-                            s_CurrentPalette.array = poa.GetArray<Material>();
-                            break;
-                        }
-                    }
                 }
                 return s_CurrentPalette;
             }
diff --git a/Editor/EditorCore/pb_ObjectArray.cs b/Editor/EditorCore/pb_ObjectArray.cs
deleted file mode 100644
index 8f5ec4e5d..000000000
--- a/Editor/EditorCore/pb_ObjectArray.cs
+++ /dev/null
@@ -1,69 +0,0 @@
-using UnityEngine;
-using System.Collections;
-using UnityEngine.ProBuilder;
-
-namespace UnityEditor.ProBuilder
-{
-    /**
-     *  Used to store arrays of materials. Made obsolete by pb_MaterialArray.
-     *
-     *  Notes:
-     *  - In the Editor folder because WebGL doesn't like ProceduralMaterial types.
-     *  - Named pb_ObjectArray because this was initially intended to be a base type for
-     *    other save-able object types. It is only used for materials, but changing the name
-     *    to something more suitable would mean breaking existing material palettes for
-     *    lots of people.
-     */
-    [System.Obsolete(
-         "pb_ObjectArray is deprecated. ProBuilder Material Editor now saves material palettes as pb_MaterialArray. You may safely delete this asset.")]
-    [System.Serializable]
-    // ReSharper disable once InconsistentNaming
-    sealed class pb_ObjectArray : ScriptableObject, IHasDefault
-    {
-        // Stored as object for backwards compatibility.
-        [SerializeField] public Object[] array;
-
-        public T[] GetArray<T>()
-        {
-            T[] arr = new T[array.Length];
-
-            for (int i = 0; i < array.Length; i++)
-            {
-                if (array[i] is ProceduralMaterial)
-                {
-                    arr[i] = (T)System.Convert.ChangeType(array[i], typeof(ProceduralMaterial));
-                }
-                else
-                {
-                    if (array[i] is T)
-                    {
-                        arr[i] = (T)System.Convert.ChangeType(array[i], typeof(T));
-                    }
-                    else
-                    {
-                        arr[i] = default(T);
-                    }
-                }
-            }
-
-            return (T[])arr;
-        }
-
-        public void SetDefaultValues()
-        {
-            array = new Material[10]
-            {
-                null,
-                null,
-                null,
-                null,
-                null,
-                null,
-                null,
-                null,
-                null,
-                null
-            };
-        }
-    }
-}
diff --git a/Editor/EditorCore/pb_ObjectArray.cs.meta b/Editor/EditorCore/pb_ObjectArray.cs.meta
deleted file mode 100644
index c9a0aef3e..000000000
--- a/Editor/EditorCore/pb_ObjectArray.cs.meta
+++ /dev/null
@@ -1,7 +0,0 @@
-fileFormatVersion: 2
-guid: c8a5a39fbad44b97b5f27e8a2e28aecf
-MonoImporter:
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}