diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 002ac899ca2b7622b0987fdbf8b5b8dba06b71ab..97b5878ceaeebde33bcfe65013dce37e710b2073 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -14,6 +14,11 @@ Changed
 
 * Wrap all imports in complete revisions to make it possible to undo them completely and to track changes correctly.
 
+Fixed
+~~~~~
+
+* Import failed if there were classes without class teachers.
+
 `2.0`_ - 2021-10-30
 -------------------
 
diff --git a/aleksis/apps/untis/util/mysql/importers/common_data.py b/aleksis/apps/untis/util/mysql/importers/common_data.py
index a2f82a9fef04f9f4d8e2f9403fdfa85e90a2fd50..4958e72ccdbd6d0529f5449847e164ed0572c88a 100644
--- a/aleksis/apps/untis/util/mysql/importers/common_data.py
+++ b/aleksis/apps/untis/util/mysql/importers/common_data.py
@@ -179,7 +179,7 @@ def import_classes(
         # Build values
         short_name = class_.name[:16]
         name = class_.longname if class_.longname else short_name
-        teacher_ids = untis_split_first(class_.teacherids, int)
+        teacher_ids = untis_split_first(class_.teacherids, int) if class_.teacherids else []
         owners = [teachers_ref[t_id] for t_id in teacher_ids]
         import_ref = class_.class_id