diff --git a/doc/source/whatsnew/v0.24.0.txt b/doc/source/whatsnew/v0.24.0.txt
index de985d4db5fa3..26478601fcde8 100644
--- a/doc/source/whatsnew/v0.24.0.txt
+++ b/doc/source/whatsnew/v0.24.0.txt
@@ -147,7 +147,7 @@ MultiIndex
 I/O
 ^^^
 
--
+- Bug in :func:`to_clipboard` which passes r'\t' instead of '\t' to to_csv (:issue:`21385`)
 -
 -
 
diff --git a/pandas/io/clipboards.py b/pandas/io/clipboards.py
index dcc221ce978b3..21c627c49b074 100644
--- a/pandas/io/clipboards.py
+++ b/pandas/io/clipboards.py
@@ -99,7 +99,7 @@ def to_clipboard(obj, excel=True, sep=None, **kwargs):  # pragma: no cover
     if excel:
         try:
             if sep is None:
-                sep = r'\t'
+                sep = '\t'
             buf = StringIO()
             # clipboard_set (pyperclip) expects unicode
             obj.to_csv(buf, sep=sep, encoding='utf-8', **kwargs)