diff --git a/CHANGELOG.md b/CHANGELOG.md
index d3f838be7d..f16ac4dbe3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - `SelectionList` option IDs are usable as soon as the widget is instantiated https://github.com/Textualize/textual/issues/3903
 - Fix issue with `Strip.crop` when crop window start aligned with strip end https://github.com/Textualize/textual/pull/3998
 - Fixed Strip.crop_extend https://github.com/Textualize/textual/pull/4011
+- Widgets could be created with IDs that you couldn't query back https://github.com/Textualize/textual/issues/3954
 
 
 ## [0.47.1] - 2023-01-05
diff --git a/tests/css/test_parse.py b/tests/css/test_parse.py
index febe4f06bb..2d6aeef002 100644
--- a/tests/css/test_parse.py
+++ b/tests/css/test_parse.py
@@ -3,8 +3,8 @@
 import pytest
 
 from textual.color import Color
-from textual.css.errors import UnresolvedVariableError
-from textual.css.parse import substitute_references
+from textual.css.errors import InvalidIDError, UnresolvedVariableError
+from textual.css.parse import substitute_references, validate_identifier
 from textual.css.scalar import Scalar, Unit
 from textual.css.stylesheet import Stylesheet, StylesheetParseError
 from textual.css.tokenize import tokenize
@@ -1272,3 +1272,40 @@ def test_parse_bad_pseudo_selector_with_suggestion():
         stylesheet.parse()
 
     assert error.value.start == (2, 7)
+
+
+@pytest.mark.parametrize(
+    "identifier",
+    [
+        "the",
+        "quick",
+        "brown",
+        "f0x",
+        "jump5",
+        "ov3r",
+        "_the__",
+        "l4zy_",
+        "_d0g",
+    ],
+)
+def test_identifier_validation_passes(identifier: str):
+    assert validate_identifier(identifier) == identifier
+
+
+@pytest.mark.parametrize(
+    "identifier",
+    [
+        " the",
+        "quick ",
+        "bro wn",
+        "f0x&",
+        "+jump5",
+        "0v3r",
+        "—the",
+        "läzy_",
+        "_d0g!",
+    ],
+)
+def test_identifier_validation_fails(identifier: str):
+    with pytest.raises(InvalidIDError):
+        validate_identifier(identifier)
diff --git a/tests/test_dom.py b/tests/test_dom.py
index 6f06fb8091..d4dc4336dd 100644
--- a/tests/test_dom.py
+++ b/tests/test_dom.py
@@ -1,6 +1,6 @@
 import pytest
 
-from textual.css.errors import StyleValueError
+from textual.css.errors import InvalidIDError, StyleValueError
 from textual.dom import BadIdentifier, DOMNode
 
 
@@ -259,3 +259,24 @@ def test_walk_children_with_self_breadth(search):
     ]
 
     assert children == ["f", "e", "d", "c", "b", "a"]
+
+
+@pytest.mark.parametrize(
+    "identifier",
+    [
+        " bad",
+        "  terrible  ",
+        "worse!  ",
+        "&ampersand",
+        "amper&sand",
+        "ampersand&",
+        "2_leading_digits",
+        "água",  # water
+        "cão",  # dog
+        "@'/.23",
+    ],
+)
+def test_id_validation(identifier: str):
+    """Regression test for https://github.com/Textualize/textual/issues/3954."""
+    with pytest.raises(InvalidIDError):
+        DOMNode(id=identifier)