diff --git a/instrumentation-genai/opentelemetry-instrumentation-langchain/src/opentelemetry/instrumentation/langchain/span_manager.py b/instrumentation-genai/opentelemetry-instrumentation-langchain/src/opentelemetry/instrumentation/langchain/span_manager.py
index 2dc307981d..636bfc3bc3 100644
--- a/instrumentation-genai/opentelemetry-instrumentation-langchain/src/opentelemetry/instrumentation/langchain/span_manager.py
+++ b/instrumentation-genai/opentelemetry-instrumentation-langchain/src/opentelemetry/instrumentation/langchain/span_manager.py
@@ -31,7 +31,7 @@
 @dataclass
 class _SpanState:
     span: Span
-    children: List[UUID] = field(default_factory=list)
+    children: List[UUID] = field(default_factory=lambda: list())
 
 
 class _SpanManager: