diff --git a/src/labapi/util/extract.py b/src/labapi/util/extract.py
index 939fe12..7ed232b 100644
--- a/src/labapi/util/extract.py
+++ b/src/labapi/util/extract.py
@@ -118,8 +118,9 @@ def extract_etree(_etree: Element, schema: EtreeExtractorDict) -> dict[str, Any]
         try:
             items[leaf] = mapper(value)
         except ValueError as err:
+            mapper_name = getattr(mapper, "__name__", repr(mapper))
             raise ExtractionError(
-                f"Could not map value {value!r} with {mapper.__name__} for "
+                f"Could not map value {value!r} with {mapper_name} for "
                 f"{message_path!r} while parsing element at {etree_path}"
             ) from err
 
diff --git a/tests/util/test_extract.py b/tests/util/test_extract.py
index b5df0f0..cfaae73 100644
--- a/tests/util/test_extract.py
+++ b/tests/util/test_extract.py
@@ -225,6 +225,31 @@ def test_extract_etree_mapper_fails_raises():
         extract_etree(element, format_dict)
 
 
+def test_extract_etree_mapper_without_name_raises():
+    """Test extract_etree raises ExtractionError properly when mapper has no __name__."""
+    from functools import partial
+
+    xml = """<?xml version="1.0" encoding="UTF-8"?>
+    <root>
+        <value>not_an_int</value>
+    </root>
+    """
+    element = etree.fromstring(bytes(xml, encoding="utf-8"))
+    mapper = partial(int, base=16)
+    format_dict: EtreeExtractorDict = {
+        "value": mapper,
+    }
+
+    with pytest.raises(
+        ExtractionError,
+        match=(
+            r"Could not map value 'not_an_int' with .*partial.* for '.+/value' while "
+            r"parsing element at /root"
+        ),
+    ):
+        extract_etree(element, format_dict)
+
+
 def test_extract_etree_warns_on_duplicate_leaf_names():
     """Test duplicate leaf extraction warns and last assignment wins."""
     xml = """<?xml version="1.0" encoding="UTF-8"?>