diff --git a/litellm/integrations/langfuse/langfuse_sdk.py b/litellm/integrations/langfuse/langfuse_sdk.py
index 0fcc7fdc573..b0d0048fde1 100644
--- a/litellm/integrations/langfuse/langfuse_sdk.py
+++ b/litellm/integrations/langfuse/langfuse_sdk.py
@@ -76,10 +76,11 @@ _LANGFUSE_INGESTION_VERSION_HEADER: Final = "x-langfuse-ingestion-version"
 _LANGFUSE_INGESTION_VERSION: Final = "4"
 _NO_REST_RETRIES: Final = RequestOptions(max_retries=0)
 _TRUNCATION_MARKER: Final = "<truncated due to size exceeding limit>"
+_METADATA_PREFIXES: Final = (LangfuseOtelSpanAttributes.OBSERVATION_METADATA, LangfuseOtelSpanAttributes.TRACE_METADATA)
 _TRUNCATION_GROUPS: Final = (
     (LangfuseOtelSpanAttributes.OBSERVATION_INPUT, LangfuseOtelSpanAttributes.TRACE_INPUT),
     (LangfuseOtelSpanAttributes.OBSERVATION_OUTPUT, LangfuseOtelSpanAttributes.TRACE_OUTPUT),
-    (LangfuseOtelSpanAttributes.OBSERVATION_METADATA, LangfuseOtelSpanAttributes.TRACE_METADATA),
+    _METADATA_PREFIXES,
 )
 _SERVER_FLOOR_HINT: Final = (
     "; the OTLP traces route needs a self-hosted Langfuse server on 3.63.0 or newer "
@@ -605,6 +606,11 @@ def _group_size(attributes: Mapping[str, AttributeValue], group: tuple[str, ...]
     )
 
 
+def _marker_key(prefix: str) -> str:
+    """Langfuse reads input and output as one string but metadata only as flattened keys, so the marker gets one."""
+    return f"{prefix}.truncated" if prefix in _METADATA_PREFIXES else prefix
+
+
 def _truncated(span: ReadableSpan) -> ReadableSpan | None:
     """The span with its largest remaining input, output or metadata replaced by the marker the v2 consumer wrote
     when an event went over ``LANGFUSE_MAX_EVENT_SIZE_BYTES``, or ``None`` once all three are gone."""
@@ -614,7 +620,9 @@ def _truncated(span: ReadableSpan) -> ReadableSpan | None:
         return None
     kept: Final = {key: value for key, value in attributes.items() if not _in_group(key, largest)}
     marked: Final = {
-        prefix: _TRUNCATION_MARKER for prefix in largest if any(_in_group(key, (prefix,)) for key in attributes)
+        _marker_key(prefix): _TRUNCATION_MARKER
+        for prefix in largest
+        if any(_in_group(key, (prefix,)) for key in attributes)
     }
     return ReadableSpan(
         name=span.name,
diff --git a/tests/test_litellm/integrations/langfuse/test_langfuse_sdk.py b/tests/test_litellm/integrations/langfuse/test_langfuse_sdk.py
index 1e5f7c07a26..765b844820e 100644
--- a/tests/test_litellm/integrations/langfuse/test_langfuse_sdk.py
+++ b/tests/test_litellm/integrations/langfuse/test_langfuse_sdk.py
@@ -1313,13 +1313,15 @@ def test_exporter_truncates_a_single_oversized_span_the_way_v2_did_instead_of_dr
 
 
 def test_exporter_truncates_largest_first_and_drops_only_when_nothing_is_left(monkeypatch, caplog):
+    """Langfuse stores a bare ``langfuse.observation.metadata`` string as nothing, so the metadata marker travels
+    under a flattened key the way every other metadata value does."""
     monkeypatch.setattr("litellm.integrations.langfuse.langfuse_sdk.sleep", lambda _: None)
     span = _generation_span(
         **{
             "langfuse.observation.input": "i" * 3000,
             "langfuse.observation.output": "o" * 2000,
             "langfuse.observation.metadata.a": "m" * 500,
-            "langfuse.observation.metadata.b": "m" * 500,
+            "langfuse.trace.metadata.b": "m" * 500,
         }
     )
     posted: list[dict[str, str]] = []
@@ -1343,9 +1345,14 @@ def test_exporter_truncates_largest_first_and_drops_only_when_nothing_is_left(mo
         [],
         ["langfuse.observation.input"],
         ["langfuse.observation.input", "langfuse.observation.output"],
-        ["langfuse.observation.input", "langfuse.observation.metadata", "langfuse.observation.output"],
+        [
+            "langfuse.observation.input",
+            "langfuse.observation.metadata.truncated",
+            "langfuse.observation.output",
+            "langfuse.trace.metadata.truncated",
+        ],
     ]
-    assert "langfuse.observation.metadata.a" not in posted[-1]
+    assert "langfuse.observation.metadata.a" not in posted[-1] and "langfuse.trace.metadata.b" not in posted[-1]
     assert "dropping it" in caplog.text