diff --git a/apprise/plugins/base.py b/apprise/plugins/base.py
index 0738a326..2f3065e8 100644
--- a/apprise/plugins/base.py
+++ b/apprise/plugins/base.py
@@ -31,6 +31,7 @@ from datetime import tzinfo
 from functools import partial
 import re
 from typing import Any, ClassVar, Optional, TypedDict, Union
+from zoneinfo import ZoneInfo
 
 from ..apprise_attachment import AppriseAttachment
 from ..common import (
@@ -875,8 +876,8 @@ class NotifyBase(URLBase):
             "overflow": self.overflow_mode.value,
         }
 
-        # Timezone Information
-        if self.__tzinfo:
+        # Timezone Information (if ZoneInfo)
+        if self.__tzinfo and isinstance(self.__tzinfo, ZoneInfo):
             params["tz"] = self.__tzinfo.key
 
         # Persistent Storage Setting
diff --git a/apprise/utils/time.py b/apprise/utils/time.py
index 5d150c73..893d55b9 100644
--- a/apprise/utils/time.py
+++ b/apprise/utils/time.py
@@ -25,6 +25,7 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 import contextlib
+from datetime import timezone as _tz
 from typing import Optional
 from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
 
@@ -40,9 +41,14 @@ def zoneinfo(name: str) -> Optional[ZoneInfo]:
     if not isinstance(name, str):
         return None
 
-    # Normalise common UTC spellings
-    if name.lower() in {"utc", "z", "gmt"}:
-        name = "UTC"
+    raw = name.strip()
+    if not raw:
+        return None
+
+    # Windows-safe: accept UTC family even without tzdata
+    if raw.lower() in {
+            "utc", "z", "gmt", "etc/utc", "etc/gmt", "gmt0", "utc0"}:
+        return _tz.utc
 
     # Try exact match first
     try:
diff --git a/pyproject.toml b/pyproject.toml
index 975c60ca..78be0783 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -45,6 +45,8 @@ dependencies = [
     "PyYAML",
     # Root certificate authority bundle
     "certifi",
+    # Always ship IANA tzdb on Windows so ZoneInfo works
+    "tzdata; platform_system == 'Windows'",
 ]
 
 # Identifies all of the supported plugins
@@ -220,6 +222,7 @@ all-plugins = [
 ]
 windows = [
     "pywin32",
+    "tzdata",
 ]
 
 [project.urls]
diff --git a/win-requirements.txt b/win-requirements.txt
index 3cd15009..7dc71239 100644
--- a/win-requirements.txt
+++ b/win-requirements.txt
@@ -4,3 +4,4 @@
 #       occur in pyproject.toml.  Contents of this file can be found
 #       in [project.optional-dependencies].windows
 pywin32
+tzdata