diff --git a/src/registrar/forms/domain.py b/src/registrar/forms/domain.py
index fd6dafb1f..2a62be15a 100644
--- a/src/registrar/forms/domain.py
+++ b/src/registrar/forms/domain.py
@@ -680,7 +680,7 @@ class DomainDsdataForm(forms.Form):
         key_tag = cleaned_data.get("key_tag", 0)
         try:
             key_tag = int(key_tag)
-            if key_tag < 0 or key_tag > 65535:
+            if key_tag <= 0 or key_tag > 65535:
                 self.add_error(
                     "key_tag",
                     DsDataError(code=DsDataErrorCodes.INVALID_KEYTAG_SIZE),
diff --git a/src/registrar/utility/errors.py b/src/registrar/utility/errors.py
index eccd118f8..dac730705 100644
--- a/src/registrar/utility/errors.py
+++ b/src/registrar/utility/errors.py
@@ -262,7 +262,7 @@ class DsDataError(Exception):
         DsDataErrorCodes.INVALID_DIGEST_SHA1: ("SHA-1 digest must be exactly 40 characters."),
         DsDataErrorCodes.INVALID_DIGEST_SHA256: ("SHA-256 digest must be exactly 64 characters."),
         DsDataErrorCodes.INVALID_DIGEST_CHARS: ("Digest must contain only alphanumeric characters (0-9, a-f)."),
-        DsDataErrorCodes.INVALID_KEYTAG_SIZE: ("Key tag must be less than 65535."),
+        DsDataErrorCodes.INVALID_KEYTAG_SIZE: ("Key tag must be greater than 0 and less than 65535."),
         DsDataErrorCodes.INVALID_KEYTAG_CHARS: ("Key tag must be numeric (0-9)."),
     }