diff --git a/docs/reference/gio/gdbus-codegen.rst b/docs/reference/gio/gdbus-codegen.rst
index 8c6eab985..7fd5011b1 100644
--- a/docs/reference/gio/gdbus-codegen.rst
+++ b/docs/reference/gio/gdbus-codegen.rst
@@ -297,8 +297,16 @@ The following options are supported:
   only one file.
 
   Since GLib 2.80, if *OUTFILE* is the literal string ``-``, the header
-  or source code will be written to standard output. To write to a file
-  starting with ``-``, it should be prefixed with ``./``.
+  or source code will be written to standard output.
+
+  For ``--body`` and ``--interface-info-body``, the generated code will not
+  automatically ``#include`` a corresponding header file when writing to
+  standard output, because there is no obvious name for that header file.
+  This might make it necessary to use ``cc -include foo.h``, or generate a
+  filename like ``foo-impl.h`` and ``#include`` it into a wrapper ``.c`` file.
+
+  In the rare situation that the intended output filename starts with ``-``,
+  it should be prefixed with ``./``.
 
 ``--annotate`` *ELEMENT* *KEY* *VALUE*
 
diff --git a/gio/gdbus-2.0/codegen/codegen.py b/gio/gdbus-2.0/codegen/codegen.py
index b1c5fb929..2e8ef8e2a 100644
--- a/gio/gdbus-2.0/codegen/codegen.py
+++ b/gio/gdbus-2.0/codegen/codegen.py
@@ -1124,15 +1124,13 @@ class InterfaceInfoBodyCodeGenerator:
 
         self.outfile.write("\n")
         self.outfile.write(
-            "#ifdef HAVE_CONFIG_H\n"
-            '#  include "config.h"\n'
-            "#endif\n"
-            "\n"
-            '#include "%s"\n'
-            "\n"
-            "#include <string.h>\n" % (self.header_name)
+            "#ifdef HAVE_CONFIG_H\n" '#  include "config.h"\n' "#endif\n" "\n"
         )
-        self.outfile.write("\n")
+
+        if self.header_name:
+            self.outfile.write('#include "%s"\n\n' % (self.header_name))
+
+        self.outfile.write("#include <string.h>\n\n")
 
     # ----------------------------------------------------------------------------------------------------
 
@@ -1472,20 +1470,21 @@ class CodeGenerator:
     def generate_body_preamble(self):
         basenames = ", ".join(self.input_files_basenames)
         self.outfile.write(LICENSE_STR.format(config.VERSION, basenames))
+
         if self.symbol_decoration_define is not None:
             self.outfile.write("\n")
             self.outfile.write("#define %s\n" % self.symbol_decoration_define)
+
         self.outfile.write("\n")
         self.outfile.write(
-            "#ifdef HAVE_CONFIG_H\n"
-            '#  include "config.h"\n'
-            "#endif\n"
-            "\n"
-            '#include "%s"\n'
-            "\n"
-            "#include <string.h>\n" % (self.header_name)
+            "#ifdef HAVE_CONFIG_H\n" '#  include "config.h"\n' "#endif\n" "\n"
         )
 
+        if self.header_name:
+            self.outfile.write('#include "%s"\n\n' % (self.header_name))
+
+        self.outfile.write("#include <string.h>\n")
+
         self.outfile.write(
             "#ifdef G_OS_UNIX\n" "#  include <gio/gunixfdlist.h>\n" "#endif\n" "\n"
         )
diff --git a/gio/gdbus-2.0/codegen/codegen_main.py b/gio/gdbus-2.0/codegen/codegen_main.py
index 58af5c654..d5353f570 100644
--- a/gio/gdbus-2.0/codegen/codegen_main.py
+++ b/gio/gdbus-2.0/codegen/codegen_main.py
@@ -336,7 +336,11 @@ def codegen_main():
             print_error("Using --body requires --output")
 
         c_file = args.output
-        header_name = os.path.splitext(os.path.basename(c_file))[0] + ".h"
+
+        if c_file == "-":
+            header_name = ""
+        else:
+            header_name = os.path.splitext(os.path.basename(c_file))[0] + ".h"
     elif args.interface_info_header:
         if args.output is None:
             print_error("Using --interface-info-header requires --output")
@@ -358,7 +362,11 @@ def codegen_main():
             )
 
         c_file = args.output
-        header_name = os.path.splitext(os.path.basename(c_file))[0] + ".h"
+
+        if c_file == "-":
+            header_name = ""
+        else:
+            header_name = os.path.splitext(os.path.basename(c_file))[0] + ".h"
 
     # Check the minimum GLib version. The minimum --glib-min-required is 2.30,
     # because that’s when gdbus-codegen was introduced. Support 1, 2 or 3
diff --git a/gio/tests/codegen.py b/gio/tests/codegen.py
index f66b92c8c..a18dcb1a9 100644
--- a/gio/tests/codegen.py
+++ b/gio/tests/codegen.py
@@ -409,8 +409,6 @@ G_END_DECLS
 
 {standard_config_h_include}
 
-#include "-.h"
-
 {standard_header_includes}
 
 {private_gvalues_getters}
@@ -432,8 +430,6 @@ G_END_DECLS
 
 {standard_config_h_include}
 
-#include "-.h"
-
 {interface_info_header_includes}""".format(
                 **result.subs
             ),