diff --git a/Doc/whatsnew/3.15.rst b/Doc/whatsnew/3.15.rst
index 4882ddb4310fc2..f70c2e5d36b1f9 100644
--- a/Doc/whatsnew/3.15.rst
+++ b/Doc/whatsnew/3.15.rst
@@ -824,6 +824,9 @@ xml.parsers.expat
 
   .. _billion laughs: https://en.wikipedia.org/wiki/Billion_laughs_attack
 
+* Add support for `namespace prefixes <https://www.w3.org/TR/xml-names/#dt-prefix>`_.
+  (Contributed by Yassir Karroum in :gh:`118317`.)
+
 
 zlib
 ----
diff --git a/Lib/test/test_sax.py b/Lib/test/test_sax.py
index 5c10bcedc69bc6..46975e351b42f9 100644
--- a/Lib/test/test_sax.py
+++ b/Lib/test/test_sax.py
@@ -1,7 +1,6 @@
 # regression test for SAX 2.0
-
 from xml.sax import make_parser, ContentHandler, \
-                    SAXException, SAXReaderNotAvailable, SAXParseException
+                    SAXException, SAXReaderNotAvailable, SAXParseException, handler
 import unittest
 from unittest import mock
 try:
@@ -1307,6 +1306,23 @@ def test_expat_locator_withinfo_nonascii(self):
         self.assertEqual(parser.getSystemId(), fname)
         self.assertEqual(parser.getPublicId(), None)
 
+    def test_qualified_names(self):
+
+        class Handler(ContentHandler):
+            def startElementNS(self, name, qname, attrs):
+                self.qname = qname
+
+        for xml_s, expected_qname in zip(["<Q:E xmlns:Q='http://example.org/testuri'/>", "<E xmlns='http://example.org/testuri'/>", "<E />"], ["Q:E", "E", "E"]):
+            parser = create_parser()
+            parser.setFeature(handler.feature_namespaces, 1)
+            parser.setFeature(handler.feature_namespace_prefixes, 1)
+
+            h = Handler()
+
+            parser.setContentHandler(h)
+            parser.parse(StringIO(xml_s))
+            self.assertEqual(h.qname, expected_qname)
+
 
 # ===========================================================================
 #
diff --git a/Lib/xml/sax/expatreader.py b/Lib/xml/sax/expatreader.py
index ba3c1e98517429..0388f2c5cdc7b9 100644
--- a/Lib/xml/sax/expatreader.py
+++ b/Lib/xml/sax/expatreader.py
@@ -81,7 +81,7 @@ def getSystemId(self):
 class ExpatParser(xmlreader.IncrementalParser, xmlreader.Locator):
     """SAX driver for the pyexpat C module."""
 
-    def __init__(self, namespaceHandling=0, bufsize=2**16-20):
+    def __init__(self, namespaceHandling=0, namespacePrefixesHandling=0, bufsize=2**16-20):
         xmlreader.IncrementalParser.__init__(self, bufsize)
         self._source = xmlreader.InputSource()
         self._parser = None
@@ -91,6 +91,7 @@ def __init__(self, namespaceHandling=0, bufsize=2**16-20):
         self._entity_stack = []
         self._external_ges = 0
         self._interning = None
+        self._namespace_prefixes = namespacePrefixesHandling
 
     # XMLReader methods
 
@@ -126,8 +127,9 @@ def getFeature(self, name):
             return self._namespaces
         elif name == feature_string_interning:
             return self._interning is not None
-        elif name in (feature_validation, feature_external_pes,
-                      feature_namespace_prefixes):
+        elif name == feature_namespace_prefixes:
+            return self._namespace_prefixes
+        elif name in (feature_validation, feature_external_pes):
             return 0
         elif name == feature_external_ges:
             return self._external_ges
@@ -147,6 +149,8 @@ def setFeature(self, name, state):
                     self._interning = {}
             else:
                 self._interning = None
+        elif name == feature_namespace_prefixes:
+            self._namespace_prefixes = state
         elif name == feature_validation:
             if state:
                 raise SAXNotSupportedException(
@@ -155,10 +159,6 @@ def setFeature(self, name, state):
             if state:
                 raise SAXNotSupportedException(
                     "expat does not read external parameter entities")
-        elif name == feature_namespace_prefixes:
-            if state:
-                raise SAXNotSupportedException(
-                    "expat does not report namespace prefixes")
         else:
             raise SAXNotRecognizedException(
                 "Feature '%s' not recognized" % name)
@@ -347,11 +347,14 @@ def start_element_ns(self, name, attrs):
         pair = name.split()
         if len(pair) == 1:
             # no namespace
+            elem_qname = name
             pair = (None, name)
         elif len(pair) == 3:
+            elem_qname = "%s:%s" % (pair[2], pair[1])
             pair = pair[0], pair[1]
         else:
             # default namespace
+            elem_qname = pair[1]
             pair = tuple(pair)
 
         newattrs = {}
@@ -374,7 +377,7 @@ def start_element_ns(self, name, attrs):
             newattrs[apair] = value
             qnames[apair] = qname
 
-        self._cont_handler.startElementNS(pair, None,
+        self._cont_handler.startElementNS(pair, elem_qname,
                                           AttributesNSImpl(newattrs, qnames))
 
     def end_element_ns(self, name):
diff --git a/Misc/NEWS.d/next/Library/2024-04-26-14-21-04.gh-issue-54873.vf2bfp.rst b/Misc/NEWS.d/next/Library/2024-04-26-14-21-04.gh-issue-54873.vf2bfp.rst
new file mode 100644
index 00000000000000..92c90c19b85dba
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-04-26-14-21-04.gh-issue-54873.vf2bfp.rst
@@ -0,0 +1,2 @@
+Backported namespaces prefixes support for xml.sax.expatreader from PyXml
+(0.8.4)