diff --git a/gtkdochelper.py b/gtkdochelper.py
index f27b2b5ee..47090125b 100755
--- a/gtkdochelper.py
+++ b/gtkdochelper.py
@@ -17,7 +17,7 @@ import sys, os
 import subprocess
 import shutil
 
-def build_gtkdoc(source_root, build_root, doc_subdir, src_subdir, main_sgml, module):
+def build_gtkdoc(source_root, build_root, doc_subdir, src_subdir, main_file, module):
     abs_src = os.path.join(source_root, src_subdir)
     abs_out = os.path.join(build_root, doc_subdir)
     htmldir = os.path.join(abs_out, 'html')
@@ -25,14 +25,19 @@ def build_gtkdoc(source_root, build_root, doc_subdir, src_subdir, main_sgml, mod
                            '--module=' + module,
                            '--source-dir=' + abs_src,
                            '--output-dir=.'], cwd=abs_out)
+    if main_file.endswith('sgml'):
+        modeflag = '--sgml-mode'
+    else:
+        modeflag = '--xml-mode'
     mkdb_cmd = ['gtkdoc-mkdb',
                 '--module=' + module,
                 '--output-format=xml',
-                '--sgml-mode',
+                modeflag,
                 '--source-dir=' + abs_src]
-    sgml_abs = os.path.join(source_root, doc_subdir, main_sgml)
+    main_abs = os.path.join(source_root, doc_subdir, main_file)
     if len(main_sgml) > 0:
-        mkdb_cmd.append('--main-sgml-file=' + sgml_abs)
+        # Yes, this is the flag even if the file is in xml.
+        mkdb_cmd.append('--main-sgml-file=' + main_abs)
     subprocess.check_call(mkdb_cmd, cwd=abs_out)
     shutil.rmtree(htmldir, ignore_errors=True)
     try:
@@ -40,11 +45,11 @@ def build_gtkdoc(source_root, build_root, doc_subdir, src_subdir, main_sgml, mod
     except Exception:
         pass
     mkhtml_cmd = ['gtkdoc-mkhtml', module]
-    if len(main_sgml) > 0:
+    if len(main_file) > 0:
         # Workaround for
         # https://bugzilla.gnome.org/show_bug.cgi?id=753145
-        plainfile = os.path.split(sgml_abs)[1]
-        shutil.copy(sgml_abs, os.path.join(abs_out, plainfile))
+        plainfile = os.path.split(main_abs)[1]
+        shutil.copy(main_abs, os.path.join(abs_out, plainfile))
         mkhtml_cmd.append('../' + plainfile)
     else:
         mkhtml_cmd.append('../%s-docs.xml' % module)
diff --git a/modules/gnome.py b/modules/gnome.py
index 43c053766..0295b03d5 100644
--- a/modules/gnome.py
+++ b/modules/gnome.py
@@ -184,9 +184,16 @@ class GnomeModule:
             raise MesonException('Gtkdoc arg must be string.')
         if not 'src_dir' in kwargs:
             raise MesonException('Keyword argument src_dir missing.')
-        main_sgml = kwargs.get('main_sgml', '')
-        if not isinstance(main_sgml, str):
+        main_file = kwargs.get('main_sgml', '')
+        if not isinstance(main_file, str):
             raise MesonException('Main sgml keyword argument must be a string.')
+        main_xml = kwargs.get('main_xml', '')
+        if not isinstance(main_xml, str):
+            raise MesonException('Main xml keyword argument must be a string.')
+        if main_xml != '':
+            if main_file != '':
+                raise MesonException('You can only specify main_xml or main_sgml, not both.')
+            main_file = main_xml
         src_dir = kwargs['src_dir']
         targetname = modulename + '-doc'
         command = os.path.normpath(os.path.join(os.path.split(__file__)[0], "../gtkdochelper.py"))
@@ -194,7 +201,7 @@ class GnomeModule:
                 state.environment.get_build_dir(),
                 state.subdir,
                 os.path.normpath(os.path.join(state.subdir, src_dir)),
-                main_sgml,
+                main_file,
                 modulename]
         res = [build.RunTarget(targetname, command, args, state.subdir)]
         if kwargs.get('install', True):