diff --git a/packages/reflex-base/src/reflex_base/environment.py b/packages/reflex-base/src/reflex_base/environment.py
index 33461cc19fc..9381d064515 100644
--- a/packages/reflex-base/src/reflex_base/environment.py
+++ b/packages/reflex-base/src/reflex_base/environment.py
@@ -405,7 +405,13 @@ def __init__(self, name: str, default: Any, type_: T) -> None:
             name: The environment variable name.
             default: The default value.
             type_: The type of the value.
+
+        Raises:
+            ValueError: If the name is not fully uppercase.
         """
+        if not name.isupper():
+            msg = f"Environment variable name must be uppercase: {name!r}"
+            raise ValueError(msg)
         self.name = name
         self.default = default
         self.type_ = type_
diff --git a/tests/units/test_environment.py b/tests/units/test_environment.py
index d3f93165957..b5b477d5fcd 100644
--- a/tests/units/test_environment.py
+++ b/tests/units/test_environment.py
@@ -437,6 +437,27 @@ def test_set_list_value(self):
         del os.environ["TEST_VAR"]
 
 
+@pytest.mark.parametrize("name", ["test_var", "Test_Var", "tEST_VAR", "reflex_use_npm"])
+def test_env_var_name_not_uppercase_raises(name):
+    """Test that a non-uppercase environment variable name is rejected.
+
+    Args:
+        name: The invalid environment variable name.
+    """
+    with pytest.raises(ValueError, match="must be uppercase"):
+        EnvVar(name, "default", str)
+
+
+@pytest.mark.parametrize("name", ["TEST_VAR", "__INTERNAL_VAR", "VAR_2"])
+def test_env_var_name_uppercase_accepted(name):
+    """Test that fully uppercase environment variable names are accepted.
+
+    Args:
+        name: The valid environment variable name.
+    """
+    assert EnvVar(name, "default", str).name == name
+
+
 class TestEnvVarDescriptor:
     """Test the env_var descriptor."""