diff --git a/webknossos/Changelog.md b/webknossos/Changelog.md
index 48f470da9..abad273f1 100644
--- a/webknossos/Changelog.md
+++ b/webknossos/Changelog.md
@@ -21,6 +21,7 @@ For upgrade instructions, please check the respective _Breaking Changes_ section
 - Added options `--layer-name` and `--mag` for compress command of the CLI. [#1141](https://github.com/scalableminds/webknossos-libs/pull/1141)
 - Added options `--chunk-shape` and `--chunks-per-shard` for convert command of the CLI. [#1150](https://github.com/scalableminds/webknossos-libs/pull/1150)
 - The `from_images` method of the `Dataset` supports directories and single files as `input_path` now. [#1152](https://github.com/scalableminds/webknossos-libs/pull/1152)
+- Argument `organization_id` is mandatory for calling the `Annotation()` constructor now. [#1155](https://github.com/scalableminds/webknossos-libs/pull/1155)
 
 ### Fixed
 - Fixed issue with webknossos URL and context URL being considered different when opening a remote dataset due to trailing slashes. [#1137](https://github.com/scalableminds/webknossos-libs/pull/1137)
diff --git a/webknossos/tests/test_skeleton.py b/webknossos/tests/test_skeleton.py
index 2e5d13d14..912bcdfc4 100644
--- a/webknossos/tests/test_skeleton.py
+++ b/webknossos/tests/test_skeleton.py
@@ -65,7 +65,10 @@ def test_doc_example() -> None:
     from webknossos import Annotation
 
     annotation = Annotation(
-        name="my_annotation", dataset_name="my_dataset", voxel_size=(11, 11, 24)
+        name="my_annotation",
+        dataset_name="my_dataset",
+        voxel_size=(11, 11, 24),
+        organization_id="my_org",
     )
     group = annotation.skeleton.add_group("a group")
     tree = group.add_tree("a tree")
@@ -177,6 +180,7 @@ def test_nml_generation(tmp_path: Path) -> None:
         name="MyAnnotation",
         dataset_name="MyDataset",
         voxel_size=(1, 1, 1),
+        organization_id="my_org",
         zoom_level=0.4,
     )
 
diff --git a/webknossos/webknossos/annotation/annotation.py b/webknossos/webknossos/annotation/annotation.py
index 10e3e39e3..48d26c5d2 100644
--- a/webknossos/webknossos/annotation/annotation.py
+++ b/webknossos/webknossos/annotation/annotation.py
@@ -51,6 +51,7 @@
 from zipp import Path as ZipPath
 
 import webknossos._nml as wknml
+from webknossos.client.context import _get_context
 
 from ..dataset import (
     SEGMENTATION_CATEGORY,
@@ -149,6 +150,11 @@ def __attrs_post_init__(self) -> None:
             assert (
                 self._voxel_size is not None
             ), "Please supply a voxel_size for Annotation()."
+            if self._organization_id is None:
+                self._organization_id = _get_context().organization_id
+            assert (
+                self._organization_id is not None
+            ), "Please supply an organization_id for Annotation()."
             self.skeleton = Skeleton(
                 dataset_name=self._dataset_name,
                 voxel_size=self._voxel_size,