diff --git a/Include/Python.h b/Include/Python.h
index 76ead9e5765ec8..c71a71f875e3e4 100644
--- a/Include/Python.h
+++ b/Include/Python.h
@@ -137,7 +137,7 @@
 #include "pystate.h"
 #include "context.h"
 
-#include "pyarena.h"
+#include "cpython/pyarena.h"
 #include "modsupport.h"
 #include "compile.h"
 #include "pythonrun.h"
@@ -154,7 +154,7 @@
 
 #include "eval.h"
 
-#include "pyctype.h"
+#include "cpython/pyctype.h"
 #include "pystrtod.h"
 #include "pystrcmp.h"
 #include "fileutils.h"
diff --git a/Include/pyarena.h b/Include/cpython/pyarena.h
similarity index 100%
rename from Include/pyarena.h
rename to Include/cpython/pyarena.h
diff --git a/Include/pyctype.h b/Include/cpython/pyctype.h
similarity index 100%
rename from Include/pyctype.h
rename to Include/cpython/pyctype.h
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 0d9fdc713406c0..ef3ca276302911 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -1054,9 +1054,7 @@ PYTHON_HEADERS= \
 		$(srcdir)/Include/osmodule.h \
 		$(srcdir)/Include/patchlevel.h \
 		$(srcdir)/Include/picklebufobject.h \
-		$(srcdir)/Include/pyarena.h \
 		$(srcdir)/Include/pycapsule.h \
-		$(srcdir)/Include/pyctype.h \
 		$(srcdir)/Include/pydebug.h \
 		$(srcdir)/Include/pydtrace.h \
 		$(srcdir)/Include/pyerrors.h \
@@ -1110,6 +1108,8 @@ PYTHON_HEADERS= \
 		$(srcdir)/Include/cpython/methodobject.h \
 		$(srcdir)/Include/cpython/object.h \
 		$(srcdir)/Include/cpython/objimpl.h \
+		$(srcdir)/Include/cpython/pyarena.h \
+		$(srcdir)/Include/cpython/pyctype.h \
 		$(srcdir)/Include/cpython/pyerrors.h \
 		$(srcdir)/Include/cpython/pylifecycle.h \
 		$(srcdir)/Include/cpython/pymem.h \
diff --git a/Misc/NEWS.d/next/C API/2021-02-17-18-51-26.bpo-35134.YoQdk8.rst b/Misc/NEWS.d/next/C API/2021-02-17-18-51-26.bpo-35134.YoQdk8.rst
new file mode 100644
index 00000000000000..c3534fce68f83f
--- /dev/null
+++ b/Misc/NEWS.d/next/C API/2021-02-17-18-51-26.bpo-35134.YoQdk8.rst	
@@ -0,0 +1,3 @@
+Move pyarena.h, pyctype.h, and pytime.h into the cpython/ directory. They
+must not be included directly, as they are already included by Python.h:
+:ref:`Include Files <api-includes>`.
diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
index 711a68fcc5c7ad..89b6218a2739a5 100644
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -142,6 +142,8 @@
     <ClInclude Include="..\Include\cpython\methodobject.h" />
     <ClInclude Include="..\Include\cpython\object.h" />
     <ClInclude Include="..\Include\cpython\objimpl.h" />
+    <ClInclude Include="..\Include\cpython\pyarena.h" />
+    <ClInclude Include="..\Include\cpython\pyctype.h" />
     <ClInclude Include="..\Include\cpython\pyerrors.h" />
     <ClInclude Include="..\Include\cpython\pylifecycle.h" />
     <ClInclude Include="..\Include\cpython\pymem.h" />
@@ -226,9 +228,7 @@
     <ClInclude Include="..\Include\parser_interface.h" />
     <ClInclude Include="..\Include\picklebufobject.h" />
     <ClInclude Include="..\Include\py_curses.h" />
-    <ClInclude Include="..\Include\pyarena.h" />
     <ClInclude Include="..\Include\pycapsule.h" />
-    <ClInclude Include="..\Include\pyctype.h" />
     <ClInclude Include="..\Include\pydebug.h" />
     <ClInclude Include="..\Include\pyerrors.h" />
     <ClInclude Include="..\Include\pyexpat.h" />
diff --git a/PCbuild/pythoncore.vcxproj.filters b/PCbuild/pythoncore.vcxproj.filters
index ab826427acc688..bd8fd3433bce0a 100644
--- a/PCbuild/pythoncore.vcxproj.filters
+++ b/PCbuild/pythoncore.vcxproj.filters
@@ -177,15 +177,9 @@
     <ClInclude Include="..\Include\py_curses.h">
       <Filter>Include</Filter>
     </ClInclude>
-    <ClInclude Include="..\Include\pyarena.h">
-      <Filter>Include</Filter>
-    </ClInclude>
     <ClInclude Include="..\Include\pycapsule.h">
       <Filter>Include</Filter>
     </ClInclude>
-    <ClInclude Include="..\Include\pyctype.h">
-      <Filter>Include</Filter>
-    </ClInclude>
     <ClInclude Include="..\Include\pydebug.h">
       <Filter>Include</Filter>
     </ClInclude>
@@ -438,6 +432,12 @@
     <ClInclude Include="..\Include\cpython\object.h">
       <Filter>Include\cpython</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\cpython\pyarena.h">
+      <Filter>Include</Filter>
+    </ClInclude>
+    <ClInclude Include="..\Include\cpython\pyctype.h">
+      <Filter>Include</Filter>
+    </ClInclude>
     <ClInclude Include="..\Include\cpython\pyerrors.h">
       <Filter>Include\cpython</Filter>
     </ClInclude>
diff --git a/Parser/pegen.h b/Parser/pegen.h
index 2a165c12d252c1..3765b2425fff7e 100644
--- a/Parser/pegen.h
+++ b/Parser/pegen.h
@@ -5,7 +5,6 @@
 #include <Python.h>
 #include <token.h>
 #include <Python-ast.h>
-#include <pyarena.h>
 
 #if 0
 #define PyPARSE_YIELD_IS_KEYWORD        0x0001
diff --git a/Tools/scripts/stable_abi.py b/Tools/scripts/stable_abi.py
index 47547a97bfd318..db187be3492cca 100755
--- a/Tools/scripts/stable_abi.py
+++ b/Tools/scripts/stable_abi.py
@@ -21,9 +21,7 @@
     "genobject.h",
     "longintrepr.h",
     "parsetok.h",
-    "pyarena.h",
     "pyatomic.h",
-    "pyctype.h",
     "pydebug.h",
     "pytime.h",
     "symtable.h",