diff --git a/python315-sentinel-values/README.md b/python315-sentinel-values/README.md
new file mode 100644
index 0000000000..81a47c9583
--- /dev/null
+++ b/python315-sentinel-values/README.md
@@ -0,0 +1,3 @@
+# Python 3.15 Preview: Sentinel Values
+
+This folder provides the code examples for the Real Python tutorial [Python 3.15 Preview: Sentinel Values](https://realpython.com/python315-sentinel-values/)
diff --git a/python315-sentinel-values/config.py b/python315-sentinel-values/config.py
new file mode 100644
index 0000000000..0f803663a0
--- /dev/null
+++ b/python315-sentinel-values/config.py
@@ -0,0 +1,8 @@
+UNSET = sentinel("UNSET")
+INHERIT = sentinel("INHERITED")  # Made a typo in the variable name
+
+
+class Config:
+    AUTO = sentinel("Config.AUTO")
+    # Some code here...
+    NO_LIMIT = sentinel("NO_LIMIT")  # Forgot the qualified name
diff --git a/python315-sentinel-values/example_001.py b/python315-sentinel-values/example_001.py
new file mode 100644
index 0000000000..19980e012e
--- /dev/null
+++ b/python315-sentinel-values/example_001.py
@@ -0,0 +1 @@
+print("Hello, World!".find("z"))
diff --git a/python315-sentinel-values/example_002.py b/python315-sentinel-values/example_002.py
new file mode 100644
index 0000000000..69643f14e2
--- /dev/null
+++ b/python315-sentinel-values/example_002.py
@@ -0,0 +1,9 @@
+import configparser
+import inspect
+import typing
+import unittest.mock
+
+print(configparser._UNSET)
+print(inspect.Parameter.empty)
+print(typing.NoDefault)
+print(unittest.mock.DEFAULT)
diff --git a/python315-sentinel-values/example_003.py b/python315-sentinel-values/example_003.py
new file mode 100644
index 0000000000..fc5b8b0707
--- /dev/null
+++ b/python315-sentinel-values/example_003.py
@@ -0,0 +1,7 @@
+import pickle
+from copy import deepcopy
+
+_MISSING = object()
+print(_MISSING)
+print(deepcopy(_MISSING) is _MISSING)
+print(pickle.loads(pickle.dumps(_MISSING)) is _MISSING)
diff --git a/python315-sentinel-values/example_004.py b/python315-sentinel-values/example_004.py
new file mode 100644
index 0000000000..3eaa29bab1
--- /dev/null
+++ b/python315-sentinel-values/example_004.py
@@ -0,0 +1,4 @@
+grades = {"Jane": 90, "John": None}
+print(grades.get("John") is grades.get("Linda"))
+print("Pythonista!".find("z"))
+print("Pythonista!"["Pythonista!".find("z")])
diff --git a/python315-sentinel-values/example_005.py b/python315-sentinel-values/example_005.py
new file mode 100644
index 0000000000..1be8c48dc5
--- /dev/null
+++ b/python315-sentinel-values/example_005.py
@@ -0,0 +1,11 @@
+from copy import deepcopy
+
+
+class _MissingType:
+    def __repr__(self):
+        return "MISSING"
+
+
+MISSING = _MissingType()
+print(MISSING)
+print(deepcopy(MISSING) is MISSING)
diff --git a/python315-sentinel-values/example_006.py b/python315-sentinel-values/example_006.py
new file mode 100644
index 0000000000..8fc07eaa4b
--- /dev/null
+++ b/python315-sentinel-values/example_006.py
@@ -0,0 +1,8 @@
+import enum
+
+
+class MissingType(enum.Enum):
+    MISSING = "MISSING"
+
+
+print(MissingType.MISSING)
diff --git a/python315-sentinel-values/example_007.py b/python315-sentinel-values/example_007.py
new file mode 100644
index 0000000000..1b36cedc90
--- /dev/null
+++ b/python315-sentinel-values/example_007.py
@@ -0,0 +1,2 @@
+MISSING = sentinel("MISSING")
+print(MISSING)
diff --git a/python315-sentinel-values/example_008.py b/python315-sentinel-values/example_008.py
new file mode 100644
index 0000000000..a29a05abbc
--- /dev/null
+++ b/python315-sentinel-values/example_008.py
@@ -0,0 +1,2 @@
+UNSET = sentinel("UNSET", repr="<unset>")
+print(UNSET)
diff --git a/python315-sentinel-values/example_009.py b/python315-sentinel-values/example_009.py
new file mode 100644
index 0000000000..cf32b0cb48
--- /dev/null
+++ b/python315-sentinel-values/example_009.py
@@ -0,0 +1,10 @@
+# Both calls intentionally fail. Catch each error so you can see both.
+try:
+    sentinel("UNSET", "<unset>")
+except TypeError as error:
+    print(f"Expected TypeError: {error}")
+
+try:
+    sentinel(name="UNSET")
+except TypeError as error:
+    print(f"Expected TypeError: {error}")
diff --git a/python315-sentinel-values/example_010.py b/python315-sentinel-values/example_010.py
new file mode 100644
index 0000000000..0b5192ccc6
--- /dev/null
+++ b/python315-sentinel-values/example_010.py
@@ -0,0 +1,7 @@
+MISSING = sentinel("MISSING")
+print(bool(MISSING))
+print(hash(MISSING))
+config = {MISSING: "unset", "timeout": 30}
+print(config[MISSING])
+print(MISSING in {MISSING, 1, 2})
+print(MISSING == sentinel("MISSING"))
diff --git a/python315-sentinel-values/example_011.py b/python315-sentinel-values/example_011.py
new file mode 100644
index 0000000000..7176a0f1f2
--- /dev/null
+++ b/python315-sentinel-values/example_011.py
@@ -0,0 +1 @@
+print(sentinel("STOP") is sentinel("STOP"))
diff --git a/python315-sentinel-values/example_012.py b/python315-sentinel-values/example_012.py
new file mode 100644
index 0000000000..f4227f7b36
--- /dev/null
+++ b/python315-sentinel-values/example_012.py
@@ -0,0 +1,6 @@
+A = sentinel("A")
+B = sentinel("B")
+print(type(A) is type(B))
+print(isinstance(A, sentinel))
+print(isinstance(B, sentinel))
+print(A is B)
diff --git a/python315-sentinel-values/example_013.py b/python315-sentinel-values/example_013.py
new file mode 100644
index 0000000000..13f41b3956
--- /dev/null
+++ b/python315-sentinel-values/example_013.py
@@ -0,0 +1,5 @@
+from copy import copy, deepcopy
+
+MISSING = sentinel("MISSING")
+print(copy(MISSING) is MISSING)
+print(deepcopy(MISSING) is MISSING)
diff --git a/python315-sentinel-values/example_014.py b/python315-sentinel-values/example_014.py
new file mode 100644
index 0000000000..ba5c26adfa
--- /dev/null
+++ b/python315-sentinel-values/example_014.py
@@ -0,0 +1,11 @@
+import pickle
+from config import Config, INHERIT, UNSET
+
+print(pickle.loads(pickle.dumps(UNSET)) is UNSET)
+print(pickle.loads(pickle.dumps(Config.AUTO)) is Config.AUTO)
+# These names intentionally don't match their module/class bindings.
+for value in (INHERIT, Config.NO_LIMIT):
+    try:
+        pickle.dumps(value)
+    except pickle.PicklingError as error:
+        print(f"Expected PicklingError: {error}")
diff --git a/python315-sentinel-values/example_015.py b/python315-sentinel-values/example_015.py
new file mode 100644
index 0000000000..09d83cbeb8
--- /dev/null
+++ b/python315-sentinel-values/example_015.py
@@ -0,0 +1,6 @@
+import inspect
+
+from settings_legacy import get_setting
+
+help(get_setting)
+print(inspect.signature(get_setting))
diff --git a/python315-sentinel-values/example_016.py b/python315-sentinel-values/example_016.py
new file mode 100644
index 0000000000..1bdcbd0ac9
--- /dev/null
+++ b/python315-sentinel-values/example_016.py
@@ -0,0 +1,6 @@
+import inspect
+
+from settings_sentinel import get_setting
+
+help(get_setting)
+print(inspect.signature(get_setting))
diff --git a/python315-sentinel-values/example_017.py b/python315-sentinel-values/example_017.py
new file mode 100644
index 0000000000..caaca1f291
--- /dev/null
+++ b/python315-sentinel-values/example_017.py
@@ -0,0 +1,5 @@
+import typing
+from settings_typed_legacy import get_setting
+
+hints = typing.get_type_hints(get_setting)
+print(hints["default"])
diff --git a/python315-sentinel-values/example_018.py b/python315-sentinel-values/example_018.py
new file mode 100644
index 0000000000..9b93d260f4
--- /dev/null
+++ b/python315-sentinel-values/example_018.py
@@ -0,0 +1,5 @@
+import typing
+from settings_typed_sentinel import get_setting
+
+hints = typing.get_type_hints(get_setting)
+print(hints["default"])
diff --git a/python315-sentinel-values/example_019.py b/python315-sentinel-values/example_019.py
new file mode 100644
index 0000000000..0ff261a565
--- /dev/null
+++ b/python315-sentinel-values/example_019.py
@@ -0,0 +1,9 @@
+from profiles_legacy import apply_patch, parse_patch
+
+profile = {
+    "name": "J. Doe",
+    "bio": "Data scientist",
+    "email": "jane@example.com",
+}
+patch = parse_patch({"name": "jane", "bio": None})
+print(apply_patch(profile, patch))
diff --git a/python315-sentinel-values/example_020.py b/python315-sentinel-values/example_020.py
new file mode 100644
index 0000000000..9378489e59
--- /dev/null
+++ b/python315-sentinel-values/example_020.py
@@ -0,0 +1,5 @@
+from copy import deepcopy
+from profiles_legacy import _MISSING, parse_patch
+
+patch = parse_patch({"name": "jane", "bio": None})
+print(deepcopy(patch)["email"] is _MISSING)
diff --git a/python315-sentinel-values/example_021.py b/python315-sentinel-values/example_021.py
new file mode 100644
index 0000000000..dbaceb8076
--- /dev/null
+++ b/python315-sentinel-values/example_021.py
@@ -0,0 +1,5 @@
+import pickle
+from profiles_legacy import _MISSING, parse_patch
+
+patch = parse_patch({"name": "jane", "bio": None})
+print(pickle.loads(pickle.dumps(patch))["email"] is _MISSING)
diff --git a/python315-sentinel-values/example_022.py b/python315-sentinel-values/example_022.py
new file mode 100644
index 0000000000..c048a52a73
--- /dev/null
+++ b/python315-sentinel-values/example_022.py
@@ -0,0 +1,7 @@
+import pickle
+from copy import deepcopy
+from profiles_sentinel import MISSING, parse_patch
+
+patch = parse_patch({"name": "jane", "bio": None})
+print(deepcopy(patch)["email"] is MISSING)
+print(pickle.loads(pickle.dumps(patch))["email"] is MISSING)
diff --git a/python315-sentinel-values/example_023.py b/python315-sentinel-values/example_023.py
new file mode 100644
index 0000000000..17525c04b2
--- /dev/null
+++ b/python315-sentinel-values/example_023.py
@@ -0,0 +1,15 @@
+STOP = "done"
+
+
+def producer():
+    words = ["ready", "done", "pending"]  # Simulate produced words
+    for word in words:
+        yield word
+    yield STOP
+
+
+words_stream = producer()
+for word in words_stream:
+    if word == STOP:
+        break
+    print(f"Processing '{word}'...")
diff --git a/python315-sentinel-values/example_024.py b/python315-sentinel-values/example_024.py
new file mode 100644
index 0000000000..db100c3a6a
--- /dev/null
+++ b/python315-sentinel-values/example_024.py
@@ -0,0 +1,15 @@
+STOP = sentinel("STOP")
+
+
+def producer():
+    words = ["ready", "done", "pending"]
+    for word in words:
+        yield word
+    yield STOP
+
+
+words_stream = producer()
+for word in words_stream:
+    if word is STOP:
+        break
+    print(f"Processing '{word}'...")
diff --git a/python315-sentinel-values/missing.py b/python315-sentinel-values/missing.py
new file mode 100644
index 0000000000..a412ffd48a
--- /dev/null
+++ b/python315-sentinel-values/missing.py
@@ -0,0 +1,21 @@
+class _MissingType:
+    def __init__(self, name):
+        self._name = name
+
+    def __repr__(self):
+        return self._name
+
+    def __copy__(self):
+        return self
+
+    def __deepcopy__(self, memo):
+        return self
+
+    def __reduce__(self):
+        return self._name
+
+    def __eq__(self, other):
+        return self is other
+
+    def __hash__(self):
+        return id(self)
diff --git a/python315-sentinel-values/profiles_legacy.py b/python315-sentinel-values/profiles_legacy.py
new file mode 100644
index 0000000000..871b64188f
--- /dev/null
+++ b/python315-sentinel-values/profiles_legacy.py
@@ -0,0 +1,15 @@
+# Python 3.14 and older approach
+_MISSING = object()
+
+
+def parse_patch(form):
+    fields = ("name", "bio", "email")
+    return {field: form.get(field, _MISSING) for field in fields}
+
+
+def apply_patch(profile, patch):
+    updated = dict(profile)
+    for field, value in patch.items():
+        if value is not _MISSING:
+            updated[field] = value
+    return updated
diff --git a/python315-sentinel-values/profiles_sentinel.py b/python315-sentinel-values/profiles_sentinel.py
new file mode 100644
index 0000000000..4b35766688
--- /dev/null
+++ b/python315-sentinel-values/profiles_sentinel.py
@@ -0,0 +1,15 @@
+# Python 3.15 or newer
+MISSING = sentinel("MISSING")
+
+
+def parse_patch(form):
+    fields = ("name", "bio", "email")
+    return {field: form.get(field, MISSING) for field in fields}
+
+
+def apply_patch(profile, patch):
+    updated = dict(profile)
+    for field, value in patch.items():
+        if value is not MISSING:
+            updated[field] = value
+    return updated
diff --git a/python315-sentinel-values/ruff.toml b/python315-sentinel-values/ruff.toml
new file mode 100644
index 0000000000..daf3de5373
--- /dev/null
+++ b/python315-sentinel-values/ruff.toml
@@ -0,0 +1,4 @@
+extend = "../pyproject.toml"
+
+# The repository's pinned Ruff predates Python 3.15's sentinel built-in.
+builtins = ["sentinel"]
diff --git a/python315-sentinel-values/sentinel_type.py b/python315-sentinel-values/sentinel_type.py
new file mode 100644
index 0000000000..cf8f34ac30
--- /dev/null
+++ b/python315-sentinel-values/sentinel_type.py
@@ -0,0 +1,2 @@
+# Python 3.15 or newer
+print(sentinel)
diff --git a/python315-sentinel-values/settings_legacy.py b/python315-sentinel-values/settings_legacy.py
new file mode 100644
index 0000000000..5230518270
--- /dev/null
+++ b/python315-sentinel-values/settings_legacy.py
@@ -0,0 +1,14 @@
+# Python 3.14 and older approach
+_NO_DEFAULT = object()
+
+
+def get_setting(config, path, default=_NO_DEFAULT):
+    current = config
+    for part in path.split("."):
+        try:
+            current = current[part]
+        except (KeyError, TypeError):
+            if default is _NO_DEFAULT:
+                raise KeyError(path) from None
+            return default
+    return current
diff --git a/python315-sentinel-values/settings_sentinel.py b/python315-sentinel-values/settings_sentinel.py
new file mode 100644
index 0000000000..ecf7dfbfe3
--- /dev/null
+++ b/python315-sentinel-values/settings_sentinel.py
@@ -0,0 +1,14 @@
+# Python 3.15 or newer
+NO_DEFAULT = sentinel("NO_DEFAULT")
+
+
+def get_setting(config, path, default=NO_DEFAULT):
+    current = config
+    for part in path.split("."):
+        try:
+            current = current[part]
+        except (KeyError, TypeError):
+            if default is NO_DEFAULT:
+                raise KeyError(path) from None
+            return default
+    return current
diff --git a/python315-sentinel-values/settings_typed_legacy.py b/python315-sentinel-values/settings_typed_legacy.py
new file mode 100644
index 0000000000..f3fe1bfbbd
--- /dev/null
+++ b/python315-sentinel-values/settings_typed_legacy.py
@@ -0,0 +1,18 @@
+# Python 3.14 and older approach, with type hints
+_NO_DEFAULT = object()
+
+
+def get_setting(
+    config: dict[str, object],
+    path: str,
+    default: object = _NO_DEFAULT,
+) -> str | int:
+    current = config
+    for part in path.split("."):
+        try:
+            current = current[part]
+        except (KeyError, TypeError):
+            if default is _NO_DEFAULT:
+                raise KeyError(path) from None
+            return default
+    return current
diff --git a/python315-sentinel-values/settings_typed_sentinel.py b/python315-sentinel-values/settings_typed_sentinel.py
new file mode 100644
index 0000000000..7c36ec3786
--- /dev/null
+++ b/python315-sentinel-values/settings_typed_sentinel.py
@@ -0,0 +1,18 @@
+# Python 3.15 or newer, with type hints
+NO_DEFAULT = sentinel("NO_DEFAULT")
+
+
+def get_setting(
+    config: dict[str, object],
+    path: str,
+    default: str | int | NO_DEFAULT = NO_DEFAULT,
+) -> str | int:
+    current = config
+    for part in path.split("."):
+        try:
+            current = current[part]
+        except (KeyError, TypeError):
+            if default is NO_DEFAULT:
+                raise KeyError(path) from None
+            return default
+    return current