diff --git a/Doc/library/tarfile.rst b/Doc/library/tarfile.rst
index c2a9143702c..b1d736130e7 100644
--- a/Doc/library/tarfile.rst
+++ b/Doc/library/tarfile.rst
@@ -185,8 +185,8 @@ The following variables are available on module level:
 
 .. data:: ENCODING
 
-   The default character encoding i.e. the value from either
-   :func:`sys.getfilesystemencoding` or :func:`sys.getdefaultencoding`.
+   The default character encoding: ``'utf-8'`` on Windows,
+   :func:`sys.getfilesystemencoding` otherwise.
 
 
 .. seealso::
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 31967dd4d90..4839eb1aef1 100644
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -159,9 +159,10 @@
 #---------------------------------------------------------
 # initialization
 #---------------------------------------------------------
-ENCODING = sys.getfilesystemencoding()
-if ENCODING is None:
-    ENCODING = "ascii"
+if os.name in ("nt", "ce"):
+    ENCODING = "utf-8"
+else:
+    ENCODING = sys.getfilesystemencoding()
 
 #---------------------------------------------------------
 # Some useful functions
diff --git a/Misc/NEWS b/Misc/NEWS
index 1335dbc0d1b..5a59310ebf1 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -421,6 +421,8 @@ C-API
 Library
 -------
 
+- Issue #8784: Set tarfile default encoding to 'utf-8' on Windows.
+
 - Issue #8966: If a ctypes structure field is an array of c_char, convert its
   value to bytes instead of str (as done for c_char and c_char_p).