diff --git a/.changes/unreleased/Fixes-20230914-134708.yaml b/.changes/unreleased/Fixes-20230914-134708.yaml
new file mode 100644
index 00000000..b025e4bb
--- /dev/null
+++ b/.changes/unreleased/Fixes-20230914-134708.yaml
@@ -0,0 +1,6 @@
+kind: Fixes
+body: Disallow dunders semantic object names
+time: 2023-09-14T13:47:08.907492-07:00
+custom:
+  Author: QMalcolm
+  Issue: "149"
diff --git a/dbt_semantic_interfaces/validations/unique_valid_name.py b/dbt_semantic_interfaces/validations/unique_valid_name.py
index 7692ebf2..e744c705 100644
--- a/dbt_semantic_interfaces/validations/unique_valid_name.py
+++ b/dbt_semantic_interfaces/validations/unique_valid_name.py
@@ -59,7 +59,11 @@ class UniqueAndValidNameRule(SemanticManifestValidationRule[SemanticManifestT],
     * Names of semantic models, dimension sets and metric sets in the model are unique / valid.
     """
 
-    NAME_REGEX = re.compile(r"\A[a-z][a-z0-9_]*[a-z0-9]\Z")
+    # name must start with a lower case letter
+    # name must end with a number or lower case letter
+    # name may include lower case letters, numbers, and underscores
+    # name may not contain dunders (two sequential underscores
+    NAME_REGEX = re.compile(r"\A[a-z]((?!__)[a-z0-9_])*[a-z0-9]\Z")
 
     @staticmethod
     def check_valid_name(name: str, context: Optional[ValidationContext] = None) -> List[ValidationIssue]:  # noqa: D
@@ -69,9 +73,10 @@ def check_valid_name(name: str, context: Optional[ValidationContext] = None) ->
             issues.append(
                 ValidationError(
                     context=context,
-                    message=f"Invalid name `{name}` - names should only consist of lower case letters, numbers, "
-                    f"and underscores. In addition, names should start with a lower case letter, and should not end "
-                    f"with an underscore, and they must be at least 2 characters long.",
+                    message=f"Invalid name `{name}` - names may only contain lower case letters, numbers, "
+                    f"and underscores. Additionally, names must start with a lower case letter, cannot end "
+                    f"with an underscore, cannot contain dunders (double underscores, or __), and must be "
+                    f"at least 2 characters long.",
                 )
             )
         if name.upper() in TimeGranularity.list_names():
diff --git a/tests/validations/test_unique_valid_name.py b/tests/validations/test_unique_valid_name.py
index 3034bf00..f0906f36 100644
--- a/tests/validations/test_unique_valid_name.py
+++ b/tests/validations/test_unique_valid_name.py
@@ -206,6 +206,7 @@ def test_invalid_names() -> None:  # noqa:D
     assert UniqueAndValidNameRule.check_valid_name("_no_leading_underscore") != []
     assert UniqueAndValidNameRule.check_valid_name("no_trailing_underscore_") != []
     assert UniqueAndValidNameRule.check_valid_name("_definitely_no_leading_and_trailing_underscore_") != []
+    assert UniqueAndValidNameRule.check_valid_name("name__with__dunders") != []
 
     # time granularity values are reserved
     assert UniqueAndValidNameRule.check_valid_name("day") != []