diff -r 2c81a883d8ca Lib/test/test_xml_etree.py
--- a/Lib/test/test_xml_etree.py	Sat Nov 07 11:17:15 2015 +0200
+++ b/Lib/test/test_xml_etree.py	Sat Nov 07 14:27:01 2015 +0200
@@ -17,7 +17,7 @@ import weakref
 
 from itertools import product
 from test import support
-from test.support import TESTFN, findfile, import_fresh_module, gc_collect
+from test.support import TESTFN, findfile, import_fresh_module, gc_collect, swap_attr
 
 # pyET is the pure-Python implementation.
 #
@@ -1762,6 +1762,12 @@ class BadElementTest(ElementTestCase, un
         e.extend([ET.Element('bar')])
         self.assertRaises(ValueError, e.remove, X('baz'))
 
+    def test_recursive_repr(self):
+        # Issue #25455
+        e = ET.Element('foo')
+        with swap_attr(e, 'tag', e):
+            with self.assertRaises(RuntimeError):
+                repr(e)  # Should not crash
 
 class MutatingElementPath(str):
     def __new__(cls, elem, *args):
diff -r 2c81a883d8ca Modules/_elementtree.c
--- a/Modules/_elementtree.c	Sat Nov 07 11:17:15 2015 +0200
+++ b/Modules/_elementtree.c	Sat Nov 07 14:27:01 2015 +0200
@@ -1573,10 +1573,23 @@ static PyObject *
 static PyObject*
 element_repr(ElementObject* self)
 {
-    if (self->tag)
-        return PyUnicode_FromFormat("<Element %R at %p>", self->tag, self);
-    else
+    int status;
+
+    if (self->tag == NULL)
         return PyUnicode_FromFormat("<Element at %p>", self);
+
+    status = Py_ReprEnter((PyObject *)self);
+    if (status == 0) {
+        PyObject *res;
+        res = PyUnicode_FromFormat("<Element %R at %p>", self->tag, self);
+        Py_ReprLeave((PyObject *)self);
+        return res;
+    }
+    if (status > 0)
+        PyErr_Format(PyExc_RuntimeError,
+                     "reentrant call inside %s.__repr__",
+                     Py_TYPE(self)->tp_name);
+    return NULL;
 }
 
 /*[clinic input]