diff --git a/Doc/library/pyexpat.rst b/Doc/library/pyexpat.rst
index c0e9999f4b1270..0f3b58ef6ea5af 100644
--- a/Doc/library/pyexpat.rst
+++ b/Doc/library/pyexpat.rst
@@ -941,6 +941,13 @@ The ``errors`` module has the following attributes:
    has been breached.
 
 
+.. data:: XML_ERROR_NOT_STARTED
+
+   The parser was tried to be stopped or suspended before it started.
+
+   .. versionadded:: next
+
+
 .. rubric:: Footnotes
 
 .. [1] The encoding string included in XML output should conform to the
diff --git a/Misc/NEWS.d/next/Library/2024-11-09-15-59-51.gh-issue-126624.bN53Va.rst b/Misc/NEWS.d/next/Library/2024-11-09-15-59-51.gh-issue-126624.bN53Va.rst
new file mode 100644
index 00000000000000..468840a651c253
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-11-09-15-59-51.gh-issue-126624.bN53Va.rst
@@ -0,0 +1,2 @@
+Expose error code :data:`~xml.parsers.expat.errors.XML_ERROR_NOT_STARTED`
+of Expat >=2.6.4 in :mod:`xml.parsers.expat.errors`.
diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c
index 9733bc34f7c80a..4ebd1fb1589b59 100644
--- a/Modules/pyexpat.c
+++ b/Modules/pyexpat.c
@@ -1767,7 +1767,10 @@ struct ErrorInfo error_info_of[] = {
     {"XML_ERROR_NO_BUFFER", "a successful prior call to function XML_GetBuffer is required"},
 
     /* Added in 2.4.0. */
-    {"XML_ERROR_AMPLIFICATION_LIMIT_BREACH", "limit on input amplification factor (from DTD and entities) breached"}
+    {"XML_ERROR_AMPLIFICATION_LIMIT_BREACH", "limit on input amplification factor (from DTD and entities) breached"},
+
+    /* Added in 2.6.4. */
+    {"XML_ERROR_NOT_STARTED", "parser not started"},
 };
 
 static int