diff --git a/requirements-test.txt b/requirements-test.txt
index 10675fd8fe..2e7d6145c2 100644
--- a/requirements-test.txt
+++ b/requirements-test.txt
@@ -3,9 +3,6 @@
 # pinned tuf runtime dependencies (should auto-update and -trigger ci/cd)
 -r requirements-pinned.txt
 
-# tuf.api tests use python-dateutil
-python-dateutil
-
 # additional test tools for linting and coverage measurement
 coverage
 black
@@ -14,4 +11,3 @@ pylint
 mypy
 bandit
 types-requests
-types-python-dateutil
diff --git a/tests/test_api.py b/tests/test_api.py
index 01b9d6526b..2ef44ed76f 100755
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -16,7 +16,6 @@
 from datetime import datetime, timedelta
 from typing import ClassVar, Dict
 
-from dateutil.relativedelta import relativedelta
 from securesystemslib import hash as sslib_hash
 from securesystemslib.interface import (
     import_ed25519_privatekey_from_file,
@@ -333,15 +332,6 @@ def test_metadata_timestamp(self) -> None:
         timestamp.signed.bump_expiration(timedelta(days=365))
         self.assertEqual(timestamp.signed.expires, datetime(2031, 1, 2, 0, 0))
 
-        # Test whether dateutil.relativedelta works, this provides a much
-        # easier to use interface for callers
-        delta = relativedelta(days=1)
-        timestamp.signed.bump_expiration(delta)
-        self.assertEqual(timestamp.signed.expires, datetime(2031, 1, 3, 0, 0))
-        delta = relativedelta(years=5)
-        timestamp.signed.bump_expiration(delta)
-        self.assertEqual(timestamp.signed.expires, datetime(2036, 1, 3, 0, 0))
-
         # Create a MetaFile instance representing what we expect
         # the updated data to be.
         hashes = {
diff --git a/tuf/api/metadata.py b/tuf/api/metadata.py
index 1717682665..6adcf412da 100644
--- a/tuf/api/metadata.py
+++ b/tuf/api/metadata.py
@@ -47,7 +47,6 @@
     cast,
 )
 
-from dateutil.relativedelta import relativedelta
 from securesystemslib import exceptions as sslib_exceptions
 from securesystemslib import hash as sslib_hash
 from securesystemslib import keys as sslib_keys
@@ -501,9 +500,7 @@ def is_expired(self, reference_time: Optional[datetime] = None) -> bool:
         return reference_time >= self.expires
 
     # Modification.
-    def bump_expiration(
-        self, delta: Union[timedelta, relativedelta] = timedelta(days=1)
-    ) -> None:
+    def bump_expiration(self, delta: timedelta = timedelta(days=1)) -> None:
         """Increments the expires attribute by the passed timedelta."""
         self.expires += delta