diff --git a/CHANGELOG.md b/CHANGELOG.md
index c366dc6..44ba904 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,10 @@ All package updates & migration steps will be listed in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [4.3.1] - 2025-01-06
+### Fixed
+- `ReadOnlyListContainer` now throws `IndexOutOfRangeException` when accessed out of range.
+
 ## [4.3.0] - 2024-11-22
 ### Added
 - `Warning` and `Error` severity levels for `ValidatorError`
diff --git a/Runtime/Types/ReadOnlyListContainer.cs b/Runtime/Types/ReadOnlyListContainer.cs
index 4fc8adf..895b9b3 100644
--- a/Runtime/Types/ReadOnlyListContainer.cs
+++ b/Runtime/Types/ReadOnlyListContainer.cs
@@ -16,7 +16,15 @@ public ReadOnlyListContainer(Func<int> countFunc, Func<int, T> getterFunc)
             _getterFunc = getterFunc;
         }
 
-        public T this[int index] => _getterFunc(index);
+        public T this[int index]
+        {
+            get
+            {
+                if (index < 0 || index >= Count)
+                    throw new IndexOutOfRangeException();
+                return _getterFunc(index);
+            }
+        }
 
         public int Count
         {
diff --git a/Tests/Runtime/Types/ReadOnlyListContainerTest.cs b/Tests/Runtime/Types/ReadOnlyListContainerTest.cs
index afefc41..716c4a3 100644
--- a/Tests/Runtime/Types/ReadOnlyListContainerTest.cs
+++ b/Tests/Runtime/Types/ReadOnlyListContainerTest.cs
@@ -41,6 +41,23 @@ public void ReadingValues()
             _countFunc.Received(1);
         }
 
+        [Test]
+        public void ReadingOutOfBounds()
+        {
+            int length = 2;
+            var container = new ReadOnlyListContainer<int>(() => length, x => 0);
+
+            // trying to access outside of the length throws an exception
+            Assert.Throws<IndexOutOfRangeException>(() => {
+                _ = container[length];
+            });
+
+                        // trying to access outside of the length throws an exception
+            Assert.Throws<IndexOutOfRangeException>(() => {
+                _ = container[-1];
+            });
+        }
+
         [Test]
         public void Enumerator()
         {
diff --git a/package.json b/package.json
index 5672466..03f0080 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "com.pocketgems.scriptableobject.flatbuffer",
-  "version": "4.3.0",
+  "version": "4.3.1",
   "displayName": "Scriptable Object - FlatBuffer",
   "description": "Seamless syncing between Scriptable Objects and CSVs.  Scriptable Object data built to Google FlatBuffers for optimal runtime loading & access.",
   "unity": "2021.3",