diff --git Lib/test/test_xml_etree.py Lib/test/test_xml_etree.py
index f1990d1..b85319f 100644
--- Lib/test/test_xml_etree.py
+++ Lib/test/test_xml_etree.py
@@ -1271,6 +1271,14 @@ XINCLUDE["C2.xml"] = """\
 
 XINCLUDE["count.txt"] = "324387"
 
+XINCLUDE["C2b.xml"] = """\
+<?xml version='1.0'?>
+<document xmlns:xi="http://www.w3.org/2001/XInclude">
+  <p>This document has been <em>accessed</em>
+  <xi:include href="count.txt" parse="text"/> times.</p>
+</document>
+"""
+
 XINCLUDE["C3.xml"] = """\
 <?xml version='1.0'?>
 <document xmlns:xi="http://www.w3.org/2001/XInclude">
@@ -1346,6 +1354,16 @@ def xinclude():
       324387 times.</p>
     </document>
 
+    Textual inclusion after sibling element (based on modified XInclude C.2)
+
+    >>> document = xinclude_loader("C2b.xml")
+    >>> ElementInclude.include(document, xinclude_loader)
+    >>> print(serialize(document)) # C2b
+    <document>
+      <p>This document has been <em>accessed</em>
+      324387 times.</p>
+    </document>
+
     Textual inclusion of XML example (XInclude C.3)
 
     >>> document = xinclude_loader("C3.xml")
diff --git Lib/xml/etree/ElementInclude.py Lib/xml/etree/ElementInclude.py
index dde0a41..84fd754 100644
--- Lib/xml/etree/ElementInclude.py
+++ Lib/xml/etree/ElementInclude.py
@@ -125,7 +125,7 @@ def include(elem, loader=None):
                         )
                 if i:
                     node = elem[i-1]
-                    node.tail = (node.tail or "") + text
+                    node.tail = (node.tail or "") + text + (e.tail or "")
                 else:
                     elem.text = (elem.text or "") + text + (e.tail or "")
                 del elem[i]