diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0fa6d145d6..49891cc60d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- `opentelemetry-sdk` - Fix the type hint of the `_metrics_data` property to allow `None` ([#4837](https://github.com/open-telemetry/opentelemetry-python/pull/4837)
+
 ## Version 1.39.0/0.60b0 (2025-12-03)
 
 - `opentelemetry-api`: Convert objects of any type other than AnyValue in attributes to string to be exportable
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/_internal/export/__init__.py b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/_internal/export/__init__.py
index caba0e15fd..cdbad3e343 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/_internal/export/__init__.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/_internal/export/__init__.py
@@ -406,7 +406,7 @@ def __init__(
             preferred_aggregation=preferred_aggregation,
         )
         self._lock = RLock()
-        self._metrics_data: MetricsData = None
+        self._metrics_data: MetricsData | None = None
 
     def get_metrics_data(
         self,