diff --git a/pystac/extensions/datacube.py b/pystac/extensions/datacube.py
index e43b8de4c..f470d0145 100644
--- a/pystac/extensions/datacube.py
+++ b/pystac/extensions/datacube.py
@@ -356,7 +356,7 @@ def ext(cls, obj: T, add_if_missing: bool = False) -> "DatacubeExtension[T]":
             return cast(DatacubeExtension[T], AssetDatacubeExtension(obj))
         else:
             raise pystac.ExtensionTypeError(
-                f"Datacube extension does not apply to type {type(obj)}"
+                f"Datacube extension does not apply to type '{type(obj).__name__}'"
             )
 
 
diff --git a/pystac/extensions/eo.py b/pystac/extensions/eo.py
index 576d1c6ba..e0a69d849 100644
--- a/pystac/extensions/eo.py
+++ b/pystac/extensions/eo.py
@@ -370,7 +370,7 @@ def ext(cls, obj: T, add_if_missing: bool = False) -> "EOExtension[T]":
             return cast(EOExtension[T], AssetEOExtension(obj))
         else:
             raise pystac.ExtensionTypeError(
-                f"EO extension does not apply to type {type(obj)}"
+                f"EO extension does not apply to type '{type(obj).__name__}'"
             )
 
     @staticmethod
diff --git a/pystac/extensions/file.py b/pystac/extensions/file.py
index deb1df4b0..6d8a76830 100644
--- a/pystac/extensions/file.py
+++ b/pystac/extensions/file.py
@@ -206,7 +206,7 @@ def ext(cls, obj: pystac.Asset, add_if_missing: bool = False) -> "FileExtension"
             return cls(obj)
         else:
             raise pystac.ExtensionTypeError(
-                f"File Info extension does not apply to type {type(obj)}"
+                f"File Info extension does not apply to type '{type(obj).__name__}'"
             )
 
 
diff --git a/pystac/extensions/item_assets.py b/pystac/extensions/item_assets.py
index f85451c0f..dea93ece8 100644
--- a/pystac/extensions/item_assets.py
+++ b/pystac/extensions/item_assets.py
@@ -126,7 +126,7 @@ def ext(
             return cls(obj)
         else:
             raise pystac.ExtensionTypeError(
-                f"Item Assets extension does not apply to type {type(obj)}"
+                f"Item Assets extension does not apply to type '{type(obj).__name__}'"
             )
 
 
diff --git a/pystac/extensions/label.py b/pystac/extensions/label.py
index 9600299d3..5ad899dff 100644
--- a/pystac/extensions/label.py
+++ b/pystac/extensions/label.py
@@ -710,7 +710,7 @@ def ext(cls, obj: pystac.Item, add_if_missing: bool = False) -> "LabelExtension"
             return cls(obj)
         else:
             raise pystac.ExtensionTypeError(
-                f"Label extension does not apply to type {type(obj)}"
+                f"Label extension does not apply to type '{type(obj).__name__}'"
             )
 
     @staticmethod
diff --git a/pystac/extensions/pointcloud.py b/pystac/extensions/pointcloud.py
index 804fed2c2..092a2ea22 100644
--- a/pystac/extensions/pointcloud.py
+++ b/pystac/extensions/pointcloud.py
@@ -536,7 +536,7 @@ def ext(cls, obj: T, add_if_missing: bool = False) -> "PointcloudExtension[T]":
             return cast(PointcloudExtension[T], AssetPointcloudExtension(obj))
         else:
             raise pystac.ExtensionTypeError(
-                f"Pointcloud extension does not apply to type {type(obj)}"
+                f"Pointcloud extension does not apply to type '{type(obj).__name__}'"
             )
 
 
diff --git a/pystac/extensions/projection.py b/pystac/extensions/projection.py
index 1c68c9fa0..a615d6500 100644
--- a/pystac/extensions/projection.py
+++ b/pystac/extensions/projection.py
@@ -261,7 +261,7 @@ def ext(cls, obj: T, add_if_missing: bool = False) -> "ProjectionExtension[T]":
             return cast(ProjectionExtension[T], AssetProjectionExtension(obj))
         else:
             raise pystac.ExtensionTypeError(
-                f"Projection extension does not apply to type {type(obj)}"
+                f"Projection extension does not apply to type '{type(obj).__name__}'"
             )
 
     @staticmethod
diff --git a/pystac/extensions/raster.py b/pystac/extensions/raster.py
index 551474b17..55e8d475c 100644
--- a/pystac/extensions/raster.py
+++ b/pystac/extensions/raster.py
@@ -706,7 +706,7 @@ def ext(cls, obj: pystac.Asset, add_if_missing: bool = False) -> "RasterExtensio
             return cls(obj)
         else:
             raise pystac.ExtensionTypeError(
-                f"Raster extension does not apply to type {type(obj)}"
+                f"Raster extension does not apply to type '{type(obj).__name__}'"
             )
 
     @staticmethod
diff --git a/pystac/extensions/sat.py b/pystac/extensions/sat.py
index a84cb0b14..c775f56c2 100644
--- a/pystac/extensions/sat.py
+++ b/pystac/extensions/sat.py
@@ -109,7 +109,7 @@ def ext(cls, obj: T, add_if_missing: bool = False) -> "SatExtension[T]":
             return cast(SatExtension[T], AssetSatExtension(obj))
         else:
             raise pystac.ExtensionTypeError(
-                f"File extension does not apply to type {type(obj)}"
+                f"Satellite extension does not apply to type '{type(obj).__name__}'"
             )
 
 
diff --git a/pystac/extensions/scientific.py b/pystac/extensions/scientific.py
index fff9f3ce1..f27cea902 100644
--- a/pystac/extensions/scientific.py
+++ b/pystac/extensions/scientific.py
@@ -248,7 +248,7 @@ def ext(cls, obj: T, add_if_missing: bool = False) -> "ScientificExtension[T]":
             return cast(ScientificExtension[T], ItemScientificExtension(obj))
         else:
             raise pystac.ExtensionTypeError(
-                f"File extension does not apply to type {type(obj)}"
+                f"Scientific extension does not apply to type '{type(obj).__name__}'"
             )
 
     @staticmethod
diff --git a/pystac/extensions/timestamps.py b/pystac/extensions/timestamps.py
index f4de30851..6eef84969 100644
--- a/pystac/extensions/timestamps.py
+++ b/pystac/extensions/timestamps.py
@@ -130,7 +130,7 @@ def ext(cls, obj: T, add_if_missing: bool = False) -> "TimestampsExtension[T]":
             return cast(TimestampsExtension[T], AssetTimestampsExtension(obj))
         else:
             raise pystac.ExtensionTypeError(
-                f"File extension does not apply to type {type(obj)}"
+                f"Timestamps extension does not apply to type '{type(obj).__name__}'"
             )
 
 
diff --git a/pystac/extensions/version.py b/pystac/extensions/version.py
index ac01dbdc2..00dc671d1 100644
--- a/pystac/extensions/version.py
+++ b/pystac/extensions/version.py
@@ -219,7 +219,7 @@ def ext(cls, obj: T, add_if_missing: bool = False) -> "VersionExtension[T]":
             return cast(VersionExtension[T], ItemVersionExtension(obj))
         else:
             raise pystac.ExtensionTypeError(
-                f"File extension does not apply to type {type(obj)}"
+                f"Version extension does not apply to type '{type(obj).__name__}'"
             )
 
 
diff --git a/tests/extensions/test_custom.py b/tests/extensions/test_custom.py
index 4c9d9c889..4e22b34a3 100644
--- a/tests/extensions/test_custom.py
+++ b/tests/extensions/test_custom.py
@@ -62,7 +62,7 @@ def custom_ext(obj: T) -> "CustomExtension[T]":
             return cast(CustomExtension[T], CatalogCustomExtension(obj))
 
         raise pystac.ExtensionTypeError(
-            f"Custom extension does not apply to {type(obj)}"
+            f"Custom extension does not apply to {type(obj).__name__}"
         )
 
     @staticmethod
diff --git a/tests/extensions/test_datacube.py b/tests/extensions/test_datacube.py
index 251bd7f83..68ea84e43 100644
--- a/tests/extensions/test_datacube.py
+++ b/tests/extensions/test_datacube.py
@@ -1,5 +1,6 @@
 import unittest
 import pystac
+from pystac import ExtensionTypeError
 from pystac.extensions.datacube import DatacubeExtension
 
 from tests.utils import TestCases
@@ -50,3 +51,13 @@ def test_asset_ext_add_to(self) -> None:
         _ = DatacubeExtension.ext(asset, add_if_missing=True)
 
         self.assertIn(DatacubeExtension.get_schema_uri(), item.stac_extensions)
+
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^Datacube extension does not apply to type 'object'$",
+            DatacubeExtension.ext,
+            object(),
+        )
diff --git a/tests/extensions/test_eo.py b/tests/extensions/test_eo.py
index 6cf3b0af8..c1ba016cb 100644
--- a/tests/extensions/test_eo.py
+++ b/tests/extensions/test_eo.py
@@ -2,7 +2,7 @@
 import unittest
 
 import pystac
-from pystac import Item
+from pystac import ExtensionTypeError, Item
 from pystac.summaries import RangeSummary
 from pystac.utils import get_opt
 from pystac.extensions.eo import EOExtension, Band
@@ -298,3 +298,13 @@ def test_asset_ext_add_to(self) -> None:
         _ = EOExtension.ext(asset, add_if_missing=True)
 
         self.assertIn(EOExtension.get_schema_uri(), item.stac_extensions)
+
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^EO extension does not apply to type 'object'$",
+            EOExtension.ext,
+            object(),
+        )
diff --git a/tests/extensions/test_file.py b/tests/extensions/test_file.py
index 35164b536..e73f83806 100644
--- a/tests/extensions/test_file.py
+++ b/tests/extensions/test_file.py
@@ -2,6 +2,7 @@
 import unittest
 
 import pystac
+from pystac import ExtensionTypeError
 from tests.utils import TestCases, assert_to_from_dict
 from pystac.extensions.file import FileExtension, ByteOrder, MappingObject
 
@@ -218,3 +219,13 @@ def test_ext_add_to(self) -> None:
         _ = FileExtension.ext(asset, add_if_missing=True)
 
         self.assertIn(FileExtension.get_schema_uri(), item.stac_extensions)
+
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^File Info extension does not apply to type 'object'$",
+            FileExtension.ext,
+            object(),
+        )
diff --git a/tests/extensions/test_label.py b/tests/extensions/test_label.py
index f46afb7c6..e7d20cdbe 100644
--- a/tests/extensions/test_label.py
+++ b/tests/extensions/test_label.py
@@ -5,7 +5,7 @@
 from typing import List, Union
 
 import pystac
-from pystac import Catalog, Collection, Item, CatalogType
+from pystac import Catalog, Collection, ExtensionTypeError, Item, CatalogType
 from pystac.extensions.label import (
     LabelExtension,
     LabelClasses,
@@ -540,3 +540,13 @@ def test_label_methods_summary(self) -> None:
         label_methods_summary_ext = label_ext_summaries.label_methods
         assert label_methods_summary_ext is not None
         self.assertListEqual(label_methods, label_methods_summary_ext)
+
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^Label extension does not apply to type 'object'$",
+            LabelExtension.ext,
+            object(),
+        )
diff --git a/tests/extensions/test_pointcloud.py b/tests/extensions/test_pointcloud.py
index 1a71cd057..863f4c4f4 100644
--- a/tests/extensions/test_pointcloud.py
+++ b/tests/extensions/test_pointcloud.py
@@ -291,8 +291,12 @@ def test_ext(self) -> None:
         class RandomObject:
             pass
 
-        with self.assertRaises(ExtensionTypeError):
-            PointcloudExtension.ext(RandomObject())  # type: ignore
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^Pointcloud extension does not apply to type 'RandomObject'$",
+            PointcloudExtension.ext,
+            RandomObject(),
+        )
 
     def test_extension_not_implemented(self) -> None:
         # Should raise exception if Item does not include extension URI
diff --git a/tests/extensions/test_projection.py b/tests/extensions/test_projection.py
index e28dc2e37..731441414 100644
--- a/tests/extensions/test_projection.py
+++ b/tests/extensions/test_projection.py
@@ -4,6 +4,7 @@
 from copy import deepcopy
 
 import pystac
+from pystac import ExtensionTypeError
 from pystac.extensions.projection import ProjectionExtension
 from pystac.utils import get_opt
 from tests.utils import TestCases, assert_to_from_dict
@@ -443,6 +444,16 @@ def test_asset_ext_add_to(self) -> None:
 
         self.assertIn(ProjectionExtension.get_schema_uri(), item.stac_extensions)
 
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^Projection extension does not apply to type 'object'$",
+            ProjectionExtension.ext,
+            object(),
+        )
+
 
 class ProjectionSummariesTest(unittest.TestCase):
     def setUp(self) -> None:
diff --git a/tests/extensions/test_raster.py b/tests/extensions/test_raster.py
index 825a6b86f..b2df3ffdb 100644
--- a/tests/extensions/test_raster.py
+++ b/tests/extensions/test_raster.py
@@ -2,7 +2,7 @@
 import unittest
 
 import pystac
-from pystac import Item
+from pystac import ExtensionTypeError, Item
 from pystac.utils import get_opt
 from pystac.extensions.raster import (
     Histogram,
@@ -222,3 +222,13 @@ def test_ext_add_to(self) -> None:
         _ = RasterExtension.ext(asset, add_if_missing=True)
 
         self.assertIn(RasterExtension.get_schema_uri(), item.stac_extensions)
+
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^Raster extension does not apply to type 'object'$",
+            RasterExtension.ext,
+            object(),
+        )
diff --git a/tests/extensions/test_sat.py b/tests/extensions/test_sat.py
index d55fd3e9e..686ec4e4d 100644
--- a/tests/extensions/test_sat.py
+++ b/tests/extensions/test_sat.py
@@ -5,6 +5,7 @@
 import unittest
 
 import pystac
+from pystac import ExtensionTypeError
 from pystac.extensions import sat
 from pystac.extensions.sat import SatExtension
 from tests.utils import TestCases
@@ -160,3 +161,13 @@ def test_asset_ext_add_to(self) -> None:
         _ = SatExtension.ext(asset, add_if_missing=True)
 
         self.assertIn(SatExtension.get_schema_uri(), item.stac_extensions)
+
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^Satellite extension does not apply to type 'object'$",
+            SatExtension.ext,
+            object(),
+        )
diff --git a/tests/extensions/test_scientific.py b/tests/extensions/test_scientific.py
index 99154c199..2897f4a21 100644
--- a/tests/extensions/test_scientific.py
+++ b/tests/extensions/test_scientific.py
@@ -1,6 +1,8 @@
 """Tests for pystac.tests.extensions.scientific."""
 
 import datetime
+
+from pystac import ExtensionTypeError
 from pystac.link import Link
 from pystac.collection import Summaries
 import unittest
@@ -406,6 +408,16 @@ def test_ext_add_to(self) -> None:
 
         self.assertIn(ScientificExtension.get_schema_uri(), collection.stac_extensions)
 
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^Scientific extension does not apply to type 'object'$",
+            ScientificExtension.ext,
+            object(),
+        )
+
 
 class SummariesScientificTest(unittest.TestCase):
     def setUp(self) -> None:
diff --git a/tests/extensions/test_timestamps.py b/tests/extensions/test_timestamps.py
index 6f1904965..5884a23b7 100644
--- a/tests/extensions/test_timestamps.py
+++ b/tests/extensions/test_timestamps.py
@@ -3,6 +3,7 @@
 from datetime import datetime
 
 import pystac
+from pystac import ExtensionTypeError
 from pystac.extensions.timestamps import TimestampsExtension
 from pystac.utils import get_opt, str_to_datetime, datetime_to_str
 from tests.utils import TestCases, assert_to_from_dict
@@ -222,3 +223,13 @@ def test_asset_ext_add_to(self) -> None:
         _ = TimestampsExtension.ext(asset, add_if_missing=True)
 
         self.assertIn(TimestampsExtension.get_schema_uri(), item.stac_extensions)
+
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^Timestamps extension does not apply to type 'object'$",
+            TimestampsExtension.ext,
+            object(),
+        )
diff --git a/tests/extensions/test_version.py b/tests/extensions/test_version.py
index c3aabd860..6a48d1698 100644
--- a/tests/extensions/test_version.py
+++ b/tests/extensions/test_version.py
@@ -5,6 +5,7 @@
 from typing import List, Optional
 
 import pystac
+from pystac import ExtensionTypeError
 from pystac.extensions import version
 from pystac.extensions.version import VersionExtension, VersionRelType
 from tests.utils import TestCases
@@ -27,6 +28,18 @@ def make_item(year: int) -> pystac.Item:
     return item
 
 
+class VersionExtensionTest(unittest.TestCase):
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^Version extension does not apply to type 'object'$",
+            VersionExtension.ext,
+            object(),
+        )
+
+
 class ItemVersionExtensionTest(unittest.TestCase):
     version: str = "1.2.3"
 
diff --git a/tests/serialization/test_migrate.py b/tests/serialization/test_migrate.py
index ec7a47951..59254028e 100644
--- a/tests/serialization/test_migrate.py
+++ b/tests/serialization/test_migrate.py
@@ -1,3 +1,4 @@
+from pystac import ExtensionTypeError
 from pystac.extensions.item_assets import ItemAssetsExtension
 from pystac.extensions.view import ViewExtension
 import unittest
@@ -96,3 +97,13 @@ def test_migrates_pre_1_0_0_rc1_stats_summary(self) -> None:
         )
         self.assertEqual(datetime_summary.minimum, "2015-06-23T00:00:00Z")
         self.assertEqual(datetime_summary.maximum, "2019-07-10T13:44:56Z")
+
+    def test_should_raise_exception_when_passing_invalid_extension_object(
+        self,
+    ) -> None:
+        self.assertRaisesRegex(
+            ExtensionTypeError,
+            r"^Item Assets extension does not apply to type 'object'$",
+            ItemAssetsExtension.ext,
+            object(),
+        )