diff --git a/invenio_theme_tugraz/config.py b/invenio_theme_tugraz/config.py
index 1c760bc..a655223 100644
--- a/invenio_theme_tugraz/config.py
+++ b/invenio_theme_tugraz/config.py
@@ -35,10 +35,16 @@ THEME_TUGRAZ_PRODUCTION = False
     has to be 'INVENIO_THEME_TUGRAZ_PRODUCTION'.
 """
 
+THEME_TUGRAZ_SUPPORT_EMAIL = ""
+"""Shown as contact-info on default error-page."""
+
 # Invenio-theme
 # ============
 # See https://invenio-theme.readthedocs.io/en/latest/configuration.html
 #
+THEME_500_TEMPLATE = "invenio_theme_tugraz/default_error.html"
+"""Used for any internal server errors and uncaught exceptions."""
+
 THEME_LOGO = "images/tug_logo.png"
 """TU Graz logo"""
 
diff --git a/invenio_theme_tugraz/templates/invenio_theme_tugraz/default_error.html b/invenio_theme_tugraz/templates/invenio_theme_tugraz/default_error.html
new file mode 100644
index 0000000..d6f2bfa
--- /dev/null
+++ b/invenio_theme_tugraz/templates/invenio_theme_tugraz/default_error.html
@@ -0,0 +1,21 @@
+{#
+    Copyright (C) 2024 Graz University of Technology.
+  
+    invenio-theme-tugraz is free software; you can redistribute it and/or
+    modify it under the terms of the MIT License; see LICENSE file for more
+    details.
+  #}
+
+  {% extends config.THEME_ERROR_TEMPLATE %}
+
+  {% block message %}
+    <h1> {{ _('Internal server error') }} </h1>
+    <p>
+      {{ _(
+          'Please contact <a href="mailto:{support_email}">our support</a>
+          to let us know about this error.'
+        ).format(support_email=config.THEME_TUGRAZ_SUPPORT_EMAIL)
+      }}
+    </p>
+    {# TODO: provide g.sentry_event_id here once sentry is configured, cf. invenio_theme/500.html #}
+  {% endblock message %}
diff --git a/invenio_theme_tugraz/views.py b/invenio_theme_tugraz/views.py
index 614d18e..4717504 100644
--- a/invenio_theme_tugraz/views.py
+++ b/invenio_theme_tugraz/views.py
@@ -11,7 +11,7 @@
 from functools import wraps
 from typing import Dict
 
-from flask import Blueprint, g, redirect, render_template, url_for
+from flask import Blueprint, current_app, g, redirect, render_template, url_for
 from flask_login import current_user, login_required
 from invenio_rdm_records.proxies import current_rdm_records
 from invenio_records_global_search.resources.serializers import (
@@ -86,12 +86,27 @@ def cast_to_dict(attr_dict):
     return AttrDict.to_dict(attr_dict)
 
 
+def default_error_handler(e: Exception):
+    """Called when an otherwise unhandled error occurs."""
+    # TODO: use sentry here once it's configured
+    # information we might want to log for debugging the error:
+    #   - `flask.request`, a proxy to the current http-request in which the error occured
+    #   - `flask.session`, a proxy to the current http-session
+    #   - `e`, the passed-in exception
+    # to get proxied-to objects: `flask.request._get_current_object()`
+
+    return render_template(current_app.config["THEME_500_TEMPLATE"]), 500
+
+
 def ui_blueprint(app):
     """Blueprint for the routes and resources provided by Invenio-theme-tugraz."""
     routes = app.config.get("TUG_ROUTES")
 
     blueprint.add_url_rule(routes["index"], view_func=index)
 
+    # base case for any otherwise unhandled exception
+    app.register_error_handler(Exception, default_error_handler)
+
     return blueprint