diff --git a/aleksis/apps/alsijil/models.py b/aleksis/apps/alsijil/models.py
index 0f0e72bb864590684c8eab5e90eed5eb5f444546..b13a4758744c67ffb79e4f364c3b9efd044a6bfe 100644
--- a/aleksis/apps/alsijil/models.py
+++ b/aleksis/apps/alsijil/models.py
@@ -1,7 +1,11 @@
 from django.db import models
 from django.utils.translation import gettext_lazy as _
 
+from calendarweek import CalendarWeek
+
+from aleksis.apps.chronos.models import LessonPeriod
 from aleksis.core.mixins import ExtensibleModel
+from aleksis.core.util.core_helpers import get_site_preferences
 
 
 def isidentifier(value: str) -> bool:
@@ -102,6 +106,47 @@ class LessonDocumentation(ExtensibleModel):
         verbose_name=_("Group note"), max_length=200, blank=True
     )
 
+    def _carry_over_data(self):
+        """Carry over data to directly adjacent periods in this lesson if data is not already set.
+
+        Can be deactivated using site preference ``alsijil__carry_over``.
+        """
+        following_periods = LessonPeriod.objects.filter(
+            lesson=self.lesson_period.lesson,
+            period__weekday=self.lesson_period.period.weekday,
+            period__period__gt=self.lesson_period.period.period,
+        )
+        for period in following_periods:
+            lesson_documentation = period.get_or_create_lesson_documentation(
+                CalendarWeek(
+                    week=self.week, year=self.lesson_period.lesson.get_year(self.week),
+                )
+            )
+
+            changed = False
+
+            if not lesson_documentation.topic:
+                lesson_documentation.topic = self.topic
+                changed = True
+
+            if not lesson_documentation.homework:
+                lesson_documentation.homework = self.homework
+                changed = True
+
+            if not lesson_documentation.group_note:
+                lesson_documentation.group_note = self.group_note
+                changed = True
+
+            if changed:
+                lesson_documentation.save()
+
+    def save(self, *args, **kwargs):
+        if get_site_preferences()["alsijil__carry_over"] and (
+            self.topic or self.homework or self.group_note
+        ):
+            self._carry_over_data()
+        super().save(*args, **kwargs)
+
     class Meta:
         verbose_name = _("Lesson documentation")
         verbose_name_plural = _("Lesson documentations")
diff --git a/aleksis/apps/alsijil/preferences.py b/aleksis/apps/alsijil/preferences.py
index e2a55de885f3e415d9b4e461ab3192f899af2398..e9d3d2d2c0eaca9c2d7838ab79594f860f4dc1c0 100644
--- a/aleksis/apps/alsijil/preferences.py
+++ b/aleksis/apps/alsijil/preferences.py
@@ -14,3 +14,16 @@ class BlockPersonalNotesForCancelled(BooleanPreference):
     name = "block_personal_notes_for_cancelled"
     default = True
     verbose_name = _("Block adding personal notes for cancelled lessons")
+
+
+@site_preferences_registry.register
+class CarryOverDataToNextPeriods(BooleanPreference):
+    section = alsijil
+    name = "carry_over"
+    default = True
+    verbose_name = _(
+        "Carry over data from first lesson period to the following lesson periods in lessons over multiple periods"
+    )
+    help_text = _(
+        "This will carry over data only if the data in the following periods are empty."
+    )