diff --git a/owncloud/MANIFEST.in b/owncloud/MANIFEST.in
new file mode 100644
index 0000000..3665b82
--- /dev/null
+++ b/owncloud/MANIFEST.in
@@ -0,0 +1,6 @@
+graft indico_owncloud/client
+graft indico_owncloud/static
+graft indico_owncloud/templates
+graft indico_owncloud/translations
+
+global-exclude *.pyc __pycache__ .keep
diff --git a/owncloud/README.md b/owncloud/README.md
new file mode 100644
index 0000000..2d96e65
--- /dev/null
+++ b/owncloud/README.md
@@ -0,0 +1,13 @@
+# OwnCloud integration plugin
+
+This plugin enables integration with an ownCloud server, initially for the
+purpose of attaching materials to an event or category. A new "from the cloud"
+button shows up in the materials section which enables a manager to log into his
+ownCloud account and pick files from his personal storage. Those files will be
+copied as attachments.
+
+## Changelog
+
+### 3.2
+
+- Initial release for Indico 3.2
diff --git a/owncloud/indico_owncloud/__init__.py b/owncloud/indico_owncloud/__init__.py
new file mode 100644
index 0000000..053c5d7
--- /dev/null
+++ b/owncloud/indico_owncloud/__init__.py
@@ -0,0 +1,11 @@
+# This file is part of the Indico plugins.
+# Copyright (C) 2002 - 2022 CERN
+#
+# The Indico plugins are free software; you can redistribute
+# them and/or modify them under the terms of the MIT License;
+# see the LICENSE file for more details.
+
+from indico.util.i18n import make_bound_gettext
+
+
+_ = make_bound_gettext('owncloud')
diff --git a/owncloud/indico_owncloud/blueprint.py b/owncloud/indico_owncloud/blueprint.py
new file mode 100644
index 0000000..1d0c517
--- /dev/null
+++ b/owncloud/indico_owncloud/blueprint.py
@@ -0,0 +1,17 @@
+# This file is part of the Indico plugins.
+# Copyright (C) 2002 - 2022 CERN
+#
+# The Indico plugins are free software; you can redistribute
+# them and/or modify them under the terms of the MIT License;
+# see the LICENSE file for more details.
+
+from indico.core.plugins import IndicoPluginBlueprint
+
+from indico_owncloud.controllers import RHAddCategoryAttachmentOwncloud, RHAddEventAttachmentOwncloud
+
+
+blueprint = IndicoPluginBlueprint('owncloud', 'indico_owncloud')
+blueprint.add_url_rule('/category/<int:category_id>/manage/attachments/add/owncloud', 'owncloud_category',
+                       RHAddCategoryAttachmentOwncloud, methods=('GET', 'POST'), defaults={'object_type': 'category'})
+blueprint.add_url_rule('/event/<int:event_id>/manage/attachments/add/owncloud', 'owncloud_event',
+                       RHAddEventAttachmentOwncloud, methods=('GET', 'POST'), defaults={'object_type': 'event'})
diff --git a/owncloud/indico_owncloud/client/index.js b/owncloud/indico_owncloud/client/index.js
new file mode 100644
index 0000000..3856bf1
--- /dev/null
+++ b/owncloud/indico_owncloud/client/index.js
@@ -0,0 +1,21 @@
+// This file is part of the Indico plugins.
+// Copyright (C) 2002 - 2022 CERN
+//
+// The Indico plugins are free software; you can redistribute
+// them and/or modify them under the terms of the MIT License;
+// see the LICENSE file for more details.
+
+// eslint-disable-next-line import/unambiguous
+window.setupOwncloudFilePickerWidget = ({filepickerUrl, fieldId}) => {
+  window.addEventListener('message', message => {
+    const iframe = document.querySelector('#owncloud_filepicker-file-picker');
+    if (
+      message.origin === filepickerUrl &&
+      message.source === iframe.contentWindow &&
+      message.data &&
+      message.data.files
+    ) {
+      document.getElementById(`${fieldId}-files`).value = message.data.files.join('\n');
+    }
+  });
+};
diff --git a/owncloud/indico_owncloud/client/style.scss b/owncloud/indico_owncloud/client/style.scss
new file mode 100644
index 0000000..678e672
--- /dev/null
+++ b/owncloud/indico_owncloud/client/style.scss
@@ -0,0 +1,23 @@
+// This file is part of the Indico plugins.
+// Copyright (C) 2002 - 2022 CERN
+//
+// The Indico plugins are free software; you can redistribute
+// them and/or modify them under the terms of the MIT License;
+// see the LICENSE file for more details.
+
+@import 'base/palette';
+
+form#attachment-owncloudfilepicker-form.full-width .owncloudfilepicker {
+  width: 770px;
+  height: 280px;
+  border: 1px solid $light-gray;
+}
+
+.owncloudfilepicker {
+  border: 0px none;
+  width: 100%;
+}
+
+.button-label {
+  margin-left: 0.4rem;
+}
diff --git a/owncloud/indico_owncloud/controllers.py b/owncloud/indico_owncloud/controllers.py
new file mode 100644
index 0000000..495f956
--- /dev/null
+++ b/owncloud/indico_owncloud/controllers.py
@@ -0,0 +1,64 @@
+# This file is part of the Indico plugins.
+# Copyright (C) 2002 - 2022 CERN
+#
+# The Indico plugins are free software; you can redistribute
+# them and/or modify them under the terms of the MIT License;
+# see the LICENSE file for more details.
+
+import mimetypes
+
+import requests
+from flask import flash, session
+from flask_pluginengine import render_plugin_template
+
+from indico.core.db import db
+from indico.modules.attachments.controllers.management.base import (_get_folders_protection_info,
+                                                                    _render_attachment_list, _render_protection_message)
+from indico.modules.attachments.controllers.management.category import RHCategoryAttachmentManagementBase
+from indico.modules.attachments.controllers.management.event import RHEventAttachmentManagementBase
+from indico.modules.attachments.models.attachments import Attachment, AttachmentFile, AttachmentType
+from indico.modules.attachments.models.folders import AttachmentFolder
+from indico.util.fs import secure_client_filename
+from indico.web.util import jsonify_data, jsonify_template
+
+from indico_owncloud import _
+from indico_owncloud.forms import AddAttachmentOwncloudForm
+
+
+class AddAttachmentOwncloudMixin:
+    """Add cloud storage attachment."""
+
+    def _process(self):
+        form = AddAttachmentOwncloudForm(linked_object=self.object)
+        if form.validate_on_submit():
+            files = form.data['owncloud_filepicker']['files']
+            folder = form.data['folder'] or AttachmentFolder.get_or_create_default(linked_object=self.object)
+            for f in files:
+                filename = f.split('/')[-1].split('?')[0]
+                local_filename = secure_client_filename(filename)
+                attachment = Attachment(folder=folder, user=session.user, title=local_filename,
+                                        type=AttachmentType.file, protection_mode=form.data['protection_mode'])
+                if attachment.is_self_protected:
+                    attachment.acl = form.data['acl']
+                content_type = mimetypes.guess_type(local_filename)[0] or 'application/octet-stream'
+                attachment.file = AttachmentFile(user=session.user, filename=local_filename, content_type=content_type)
+
+                file_response = requests.get(f)
+                file_response.raise_for_status()
+                attachment.file.save(file_response.content)
+
+                db.session.add(attachment)
+                db.session.flush()
+            flash(_('Attachment added'))
+            return jsonify_data(attachment_list=_render_attachment_list(self.object))
+        return jsonify_template('add_owncloud_files.html', _render_func=render_plugin_template, form=form,
+                                protection_message=_render_protection_message(self.object),
+                                folders_protection_info=_get_folders_protection_info(self.object))
+
+
+class RHAddCategoryAttachmentOwncloud(AddAttachmentOwncloudMixin, RHCategoryAttachmentManagementBase):
+    pass
+
+
+class RHAddEventAttachmentOwncloud(AddAttachmentOwncloudMixin, RHEventAttachmentManagementBase):
+    pass
diff --git a/owncloud/indico_owncloud/forms.py b/owncloud/indico_owncloud/forms.py
new file mode 100644
index 0000000..de33eab
--- /dev/null
+++ b/owncloud/indico_owncloud/forms.py
@@ -0,0 +1,45 @@
+# This file is part of the Indico plugins.
+# Copyright (C) 2002 - 2022 CERN
+#
+# The Indico plugins are free software; you can redistribute
+# them and/or modify them under the terms of the MIT License;
+# see the LICENSE file for more details.
+
+from wtforms import Field
+from wtforms.validators import DataRequired, ValidationError
+
+from indico.core.config import config
+from indico.modules.attachments.forms import AttachmentFormBase
+from indico.util.i18n import _
+from indico.web.forms.widgets import JinjaWidget
+
+from indico_owncloud.util import get_filepicker_url
+
+
+class IndicoOwncloudField(Field):
+    widget = JinjaWidget('owncloud_filepicker_widget.html', plugin='owncloud', single_line=True, single_kwargs=True)
+
+    def __init__(self, label=None, validators=None, **kwargs):
+        super().__init__(label, validators, **kwargs)
+        self.filepicker_url = get_filepicker_url()
+        self.origin = config.BASE_URL
+
+    def process_formdata(self, valuelist):
+        if valuelist:
+            self.data = {'files': [f.rstrip() for f in valuelist[0].split('\n')]}
+
+
+class AttachmentOwncloudFormMixin:
+    owncloud_filepicker = IndicoOwncloudField(_('Files'), [DataRequired()])
+
+    def validate_owncloud_filepicker(self, field):
+        if self.owncloud_filepicker.data and self.owncloud_filepicker.data['files'] == ['']:
+            raise ValidationError("Select files to add and click 'Select resources'")
+
+
+class AddAttachmentOwncloudForm(AttachmentOwncloudFormMixin, AttachmentFormBase):
+    pass
+
+
+class EditAttachmentOwncloudForm(AttachmentOwncloudFormMixin, AttachmentFormBase):
+    pass
diff --git a/owncloud/indico_owncloud/plugin.py b/owncloud/indico_owncloud/plugin.py
new file mode 100644
index 0000000..55f004c
--- /dev/null
+++ b/owncloud/indico_owncloud/plugin.py
@@ -0,0 +1,66 @@
+# This file is part of the Indico plugins.
+# Copyright (C) 2002 - 2022 CERN
+#
+# The Indico plugins are free software; you can redistribute
+# them and/or modify them under the terms of the MIT License;
+# see the LICENSE file for more details.
+
+from flask_pluginengine.plugin import render_plugin_template
+from wtforms.fields import StringField, URLField
+from wtforms.validators import DataRequired
+
+from indico.core.plugins import IndicoPlugin
+from indico.modules.attachments.views import WPEventAttachments
+from indico.modules.categories.views import WPCategoryManagement
+from indico.modules.events.views import WPConferenceDisplay, WPSimpleEventDisplay
+from indico.web.forms.base import IndicoForm
+
+from indico_owncloud import _
+from indico_owncloud.blueprint import blueprint
+from indico_owncloud.util import is_configured
+
+
+class PluginSettingsForm(IndicoForm):
+    filepicker_url = URLField(_('File-picker URL'), [DataRequired()])
+    service_name = StringField(_('Service name'), [],
+                               description=_('A customized name for the cloud service. If empty, the default '
+                                             "'The cloud' will be used."))
+    button_icon_url = URLField(_('Custom icon URL'), [],
+                               description=_('URL for a customized icon to show in the add attachment button. If '
+                                             'empty, the default cloud icon will be used'))
+
+
+class OwncloudPlugin(IndicoPlugin):
+    """OwnCloud integration
+
+    Provides an integration with OwnCloud storage servers, enabling managers
+    to attach files to categories/events from their cloud storage.
+    """
+    configurable = True
+    settings_form = PluginSettingsForm
+    default_settings = {
+        'filepicker_url': '',
+        'service_name': '',
+        'button_icon_url': '',
+    }
+
+    def init(self):
+        super().init()
+        self.template_hook('attachment-sources', self._inject_owncloud_button)
+        self.inject_bundle('owncloud.js', WPEventAttachments)
+        self.inject_bundle('owncloud.js', WPSimpleEventDisplay)
+        self.inject_bundle('owncloud.js', WPConferenceDisplay)
+        self.inject_bundle('owncloud.js', WPCategoryManagement)
+        self.inject_bundle('main.css', WPEventAttachments)
+        self.inject_bundle('main.css', WPSimpleEventDisplay)
+        self.inject_bundle('main.css', WPConferenceDisplay)
+        self.inject_bundle('main.css', WPCategoryManagement)
+
+    def get_blueprints(self):
+        return blueprint
+
+    def _inject_owncloud_button(self, linked_object=None, **kwargs):
+        if is_configured():
+            return render_plugin_template('owncloud_button.html', id=linked_object.id, linked_object=linked_object,
+                                          service_name=self.settings.get('service_name'),
+                                          button_icon_url=self.settings.get('button_icon_url'))
diff --git a/owncloud/indico_owncloud/templates/add_owncloud_files.html b/owncloud/indico_owncloud/templates/add_owncloud_files.html
new file mode 100644
index 0000000..9351d31
--- /dev/null
+++ b/owncloud/indico_owncloud/templates/add_owncloud_files.html
@@ -0,0 +1,34 @@
+{% from 'forms/_form.html' import form_header, form_footer, form_rows, form_row %}
+
+{%- block content %}
+    {{ form_header(form, id='attachment-owncloudfilepicker-form', classes=('full-width')) }}
+    {{ form_row(form.owncloud_filepicker, skip_label=true) }}
+    {{ form_rows(form, fields=('folder', 'protected', 'acl')) }}
+    {{ protection_message | safe }}
+    {% call form_footer(attach_form) %}
+        <input class="i-button big highlight" type="submit" value="{% trans %}Add{% endtrans %}">
+        <button class="i-button big" data-button-back>{% trans %}Cancel{% endtrans %}</button>
+    {% endcall %}
+    <script>
+        (function() {
+            'use strict';
+
+            $('#{{ form.folder.id }}').nullableselector();
+            const form = $('#attachment-owncloudfilepicker-form');
+            aclIfProtected(
+                $('#{{ form.protected.id }}'),
+                $('#{{ form.acl.id }}'),
+                form.find('.protected-protection-message'),
+                form.find('.inheriting-protection-message'),
+                $('#{{ form.folder.id }}')
+            );
+            messageIfFolderProtected(
+                $('#{{ form.protected.id }}'), $('#{{ form.folder.id }}'),
+                {{ folders_protection_info | tojson }},
+                $('.protected-protection-message'),
+                $('.inheriting-protection-message'),
+                $('.folder-protection-message')
+            );
+        })();
+    </script>
+{%- endblock %}
diff --git a/owncloud/indico_owncloud/templates/owncloud_button.html b/owncloud/indico_owncloud/templates/owncloud_button.html
new file mode 100644
index 0000000..b9bec45
--- /dev/null
+++ b/owncloud/indico_owncloud/templates/owncloud_button.html
@@ -0,0 +1,10 @@
+{% set service_name = service_name or _('the cloud') %}
+<a href="#" class="i-button js-dialog-action"
+   data-href="{{ url_for_plugin('owncloud.owncloud_event', event_id=id) }}"
+   data-title="{%- trans -%}Add files from {{ service_name }}{%- endtrans -%}">
+    <span class="{{ 'icon-cloud2' if not button_icon_url }}"></span>
+    {%- if button_icon_url -%}
+        <img height="24" src="{{ button_icon_url }}">
+    {%- endif -%}
+    <span class="button-label">{%- trans -%}From {{ service_name }}{%- endtrans -%}</span>
+</a>
diff --git a/owncloud/indico_owncloud/templates/owncloud_filepicker_widget.html b/owncloud/indico_owncloud/templates/owncloud_filepicker_widget.html
new file mode 100644
index 0000000..c04ce5d
--- /dev/null
+++ b/owncloud/indico_owncloud/templates/owncloud_filepicker_widget.html
@@ -0,0 +1,20 @@
+{% extends 'forms/base_widget.html' %}
+
+{% block html %}
+    {% set src = field.filepicker_url + '?origin=' + field.origin %}
+    <div class="i-form-field-fixed-width">
+        <input type="hidden" name="{{ field.name }}" id="{{ field.id }}-files" {{ input_args | html_params }}>
+        <span id="{{ field.id }}-container">
+            <iframe id="{{ field.id }}-file-picker" class="owncloudfilepicker" src="{{ src }}"></iframe>
+        </span>
+    </div>
+{% endblock %}
+
+{% block javascript %}
+    <script>
+        setupOwncloudFilePickerWidget({
+            filepickerUrl: {{ field.filepicker_url | tojson }},
+            fieldId: {{ field.id | tojson }},
+        });
+    </script>
+{% endblock %}
diff --git a/owncloud/indico_owncloud/translations/messages.pot b/owncloud/indico_owncloud/translations/messages.pot
new file mode 100644
index 0000000..d888a8c
--- /dev/null
+++ b/owncloud/indico_owncloud/translations/messages.pot
@@ -0,0 +1,73 @@
+# Translations template for PROJECT.
+# Copyright (C) 2022 ORGANIZATION
+# This file is distributed under the same license as the PROJECT project.
+# FIRST AUTHOR <EMAIL@ADDRESS>, 2022.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: PROJECT VERSION\n"
+"Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
+"POT-Creation-Date: 2022-03-16 15:30+0100\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
+"Language-Team: LANGUAGE <LL@li.org>\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=utf-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Generated-By: Babel 2.9.1\n"
+
+#: indico_owncloud/controllers.py:51
+msgid "Attachment added"
+msgstr ""
+
+#: indico_owncloud/forms.py:34
+msgid "Files"
+msgstr ""
+
+#: indico_owncloud/plugin.py:24
+msgid "File-picker URL"
+msgstr ""
+
+#: indico_owncloud/plugin.py:25
+msgid "Service name"
+msgstr ""
+
+#: indico_owncloud/plugin.py:26
+msgid ""
+"A customized name for the cloud service. If empty, the default 'The "
+"cloud' will be used."
+msgstr ""
+
+#: indico_owncloud/plugin.py:28
+msgid "Custom icon URL"
+msgstr ""
+
+#: indico_owncloud/plugin.py:29
+msgid ""
+"URL for a customized icon to show in the add attachment button. If empty,"
+" the default cloud icon will be used"
+msgstr ""
+
+#: indico_owncloud/templates/add_owncloud_files.html:9
+msgid "Add"
+msgstr ""
+
+#: indico_owncloud/templates/add_owncloud_files.html:10
+msgid "Cancel"
+msgstr ""
+
+#: indico_owncloud/templates/owncloud_button.html:1
+msgid "the cloud"
+msgstr ""
+
+#: indico_owncloud/templates/owncloud_button.html:4
+#, python-format
+msgid "Add files from %(service_name)s"
+msgstr ""
+
+#: indico_owncloud/templates/owncloud_button.html:9
+#, python-format
+msgid "From %(service_name)s"
+msgstr ""
+
diff --git a/owncloud/indico_owncloud/util.py b/owncloud/indico_owncloud/util.py
new file mode 100644
index 0000000..d9e2026
--- /dev/null
+++ b/owncloud/indico_owncloud/util.py
@@ -0,0 +1,18 @@
+# This file is part of the Indico plugins.
+# Copyright (C) 2002 - 2022 CERN
+#
+# The Indico plugins are free software; you can redistribute
+# them and/or modify them under the terms of the MIT License;
+# see the LICENSE file for more details.
+
+def is_configured():
+    """Check whether the plugin is properly configured."""
+    from indico_owncloud.plugin import OwncloudPlugin
+
+    return bool(OwncloudPlugin.settings.get('filepicker_url'))
+
+
+def get_filepicker_url():
+    from indico_owncloud.plugin import OwncloudPlugin
+
+    return OwncloudPlugin.settings.get('filepicker_url').rstrip('/')
diff --git a/owncloud/setup.cfg b/owncloud/setup.cfg
new file mode 100644
index 0000000..684c4ec
--- /dev/null
+++ b/owncloud/setup.cfg
@@ -0,0 +1,30 @@
+[metadata]
+name = indico-plugin-owncloud
+version = 3.2-dev
+description = Integrates ownCloud storage as a source for materials
+long_description = file: README.md
+long_description_content_type = text/markdown; charset=UTF-8; variant=GFM
+url = https://github.com/indico/indico-plugins
+license = MIT
+author = Indico Team
+author_email = indico-team@cern.ch
+classifiers =
+    Environment :: Plugins
+    Environment :: Web Environment
+    License :: OSI Approved :: MIT License
+    Programming Language :: Python :: 3.9
+
+[options]
+packages = find:
+zip_safe = false
+include_package_data = true
+python_requires = ~=3.9.0
+install_requires =
+    indico>=3.2.dev0
+
+[options.entry_points]
+indico.plugins =
+    owncloud = indico_owncloud.plugin:OwncloudPlugin
+
+[pydocstyle]
+ignore = D100,D101,D102,D103,D104,D105,D107,D203,D213
diff --git a/owncloud/setup.py b/owncloud/setup.py
new file mode 100644
index 0000000..a98c3c3
--- /dev/null
+++ b/owncloud/setup.py
@@ -0,0 +1,11 @@
+# This file is part of the Indico plugins.
+# Copyright (C) 2002 - 2022 CERN
+#
+# The Indico plugins are free software; you can redistribute
+# them and/or modify them under the terms of the MIT License;
+# see the LICENSE file for more details.
+
+from setuptools import setup
+
+
+setup()
diff --git a/owncloud/webpack-bundles.json b/owncloud/webpack-bundles.json
new file mode 100644
index 0000000..8640d70
--- /dev/null
+++ b/owncloud/webpack-bundles.json
@@ -0,0 +1,6 @@
+{
+  "entry": {
+    "owncloud": "./index.js",
+    "main": "./style.scss"
+  }
+}