diff --git a/.meta.toml b/.meta.toml
index 51f8d75edd..f8e05ee3c3 100644
--- a/.meta.toml
+++ b/.meta.toml
@@ -104,6 +104,7 @@ additional-rules = [
     "recursive-include src *.svg",
     "recursive-include src *.ttf",
     "recursive-include src *.txt",
+    "recursive-include src *.types",
     "recursive-include src *.webmanifest",
     "recursive-include src *.woff",
     "recursive-include src *.woff2",
diff --git a/CHANGES.rst b/CHANGES.rst
index edac84affb..af4740762a 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -10,6 +10,10 @@ https://github.com/zopefoundation/Zope/blob/4.x/CHANGES.rst
 5.9.1 (unreleased)
 ------------------
 
+- Define a custom MIME type for Zope Page Templates
+  instead of relying on platform-dependent MIME type configurations.
+  (`#1212 <https://github.com/zopefoundation/Zope/issues/1212>`_)
+
 - Clean up and fix installation documentation.
 
 - Officially support Python 3.12.1.
diff --git a/MANIFEST.in b/MANIFEST.in
index 8d9d6e273c..d7c1523a2d 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -43,6 +43,7 @@ recursive-include src *.rst
 recursive-include src *.svg
 recursive-include src *.ttf
 recursive-include src *.txt
+recursive-include src *.types
 recursive-include src *.webmanifest
 recursive-include src *.woff
 recursive-include src *.woff2
diff --git a/src/Products/PageTemplates/__init__.py b/src/Products/PageTemplates/__init__.py
index 62cac12138..19e91ba625 100644
--- a/src/Products/PageTemplates/__init__.py
+++ b/src/Products/PageTemplates/__init__.py
@@ -15,6 +15,10 @@
 This wrapper allows the Page Template modules to be segregated in a
 separate package.
 """
+import os
+
+from zope.contenttype import add_files
+
 
 # Placeholder for Zope Product data
 misc_ = {}
@@ -29,3 +33,8 @@ def initialize(context):
     # Import lazily, and defer initialization to the module
     from . import ZopePageTemplate
     ZopePageTemplate.initialize(context)
+
+    # Add the custom MIME type information for Page Templates
+    # to the Python mimetypes module so they are recognized correctly
+    here = os.path.dirname(os.path.abspath(__file__))
+    add_files([os.path.join(here, 'mime.types')])
diff --git a/src/Products/PageTemplates/mime.types b/src/Products/PageTemplates/mime.types
new file mode 100644
index 0000000000..2223b74bd5
--- /dev/null
+++ b/src/Products/PageTemplates/mime.types
@@ -0,0 +1 @@
+application/vnd.zopefoundation.pagetemplate     pt zpt
diff --git a/src/webdav/NullResource.py b/src/webdav/NullResource.py
index 02deb8ba5f..1cbbbd3568 100644
--- a/src/webdav/NullResource.py
+++ b/src/webdav/NullResource.py
@@ -114,7 +114,9 @@ def _default_PUT_factory(self, name, typ, body):
 
         if ext == '.dtml':
             ob = DTMLDocument('', __name__=name)
-        elif typ in ('text/html', 'text/xml'):
+        elif typ in ('text/html',
+                     'text/xml',
+                     'application/vnd.zopefoundation.pagetemplate'):
             ob = ZopePageTemplate(name, body, content_type=typ)
         elif typ.startswith('image/'):
             ob = Image(name, '', body, content_type=typ)