diff --git a/AUTHORS.rst b/AUTHORS.rst
index 49e1c5b7..117a8194 100644
--- a/AUTHORS.rst
+++ b/AUTHORS.rst
@@ -94,3 +94,5 @@ Contributors
 - Antoine Giraudmaillet (@antoine-g)
 
 - Paulus Schoutsen (@balloob)
+
+- Nolan Bruabker (@nrb)
diff --git a/github3/issues/milestone.py b/github3/issues/milestone.py
index 9c2726e6..96114ddb 100644
--- a/github3/issues/milestone.py
+++ b/github3/issues/milestone.py
@@ -38,6 +38,8 @@ class Milestone(GitHubCore):
         self.due_on = self._strptime(mile.get('due_on'))
         #: datetime object representing when the milestone was updated.
         self.updated_at = self._strptime(mile.get('updated_at'))
+        #: string representing the milestone's ID.
+        self.id = str(mile.get('id'))
 
     def _repr(self):
         return '<Milestone [{0}]>'.format(self)

Milestone objects don't have id attributes
```py
>>> r = g.repository('rcbops', 'rpc-openstack')
>>> milestones = list(r.milestones())
>>> milestones
[<Milestone [kilo 11.0.0]>, <Milestone [next]>, <Milestone [icehouse 9.0.10]>, <Milestone [juno 10.1.10]>, <Milestone [Kilo 11.1.0]>, <Milestone [Kilo 11.2.0]>]
>>> milestones[0].id
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'Milestone' object has no attribute 'id'
```
diff --git a/tests/test_issues.py b/tests/test_issues.py
index e85aa48c..c58275c4 100644
--- a/tests/test_issues.py
+++ b/tests/test_issues.py
@@ -77,6 +77,9 @@ class TestMilestone(BaseCase):
     def test_str(self):
         assert str(self.m) == 'v1.0.0'
 
+    def test_id(self):
+        assert self.m.id== '219754'
+
     def test_delete(self):
         self.response('', 204)
         self.delete(self.api)

pip install -e .[test]
parse_log_pytest
requirements.txt
pytest pytest-cov pytest-xdist pytest-mock pytest-asyncio
apt-get update apt-get install -y gcc
3.9
requirements.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
betamax==0.9.0
betamax-matchers==0.4.0
certifi==2025.1.31
charset-normalizer==3.4.1
coverage==7.8.0
exceptiongroup==1.2.2
execnet==2.1.1
-e git+https://github.com/sigmavirus24/github3.py.git@48adfa8a0a3884fd9e2600b90b37e27efd61eee2#egg=github3.py
idna==3.10
iniconfig==2.1.0
packaging==24.2
pluggy==1.5.0
pytest==8.3.5
pytest-asyncio==0.26.0
pytest-cov==6.0.0
pytest-mock==3.14.0
pytest-xdist==3.6.1
requests==2.32.3
requests-toolbelt==1.0.0
tomli==2.2.1
typing_extensions==4.13.0
uritemplate==4.1.1
uritemplate.py==3.0.2
urllib3==2.3.0

name: github3.py
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=3.0.16=h5eee18b_0
  - pip=25.0=py39h06a4308_0
  - python=3.9.21=he870216_1
  - readline=8.2=h5eee18b_0
  - setuptools=75.8.0=py39h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - tzdata=2025a=h04d1e81_0
  - wheel=0.45.1=py39h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - betamax==0.9.0
      - betamax-matchers==0.4.0
      - certifi==2025.1.31
      - charset-normalizer==3.4.1
      - coverage==7.8.0
      - exceptiongroup==1.2.2
      - execnet==2.1.1
      - idna==3.10
      - iniconfig==2.1.0
      - packaging==24.2
      - pluggy==1.5.0
      - pytest==8.3.5
      - pytest-asyncio==0.26.0
      - pytest-cov==6.0.0
      - pytest-mock==3.14.0
      - pytest-xdist==3.6.1
      - requests==2.32.3
      - requests-toolbelt==1.0.0
      - tomli==2.2.1
      - typing-extensions==4.13.0
      - uritemplate==4.1.1
      - uritemplate-py==3.0.2
      - urllib3==2.3.0
prefix: /opt/conda/envs/github3.py

tests/test_issues.py::TestMilestone::test_id
tests/test_issues.py::TestLabel::test_delete tests/test_issues.py::TestLabel::test_equality tests/test_issues.py::TestLabel::test_repr tests/test_issues.py::TestLabel::test_str tests/test_issues.py::TestLabel::test_update tests/test_issues.py::TestMilestone::test_delete tests/test_issues.py::TestMilestone::test_due_on tests/test_issues.py::TestMilestone::test_repr tests/test_issues.py::TestMilestone::test_str tests/test_issues.py::TestMilestone::test_update tests/test_issues.py::TestIssue::test_add_labels tests/test_issues.py::TestIssue::test_assign tests/test_issues.py::TestIssue::test_close tests/test_issues.py::TestIssue::test_comment tests/test_issues.py::TestIssue::test_create_comment tests/test_issues.py::TestIssue::test_edit tests/test_issues.py::TestIssue::test_enterprise tests/test_issues.py::TestIssue::test_equality tests/test_issues.py::TestIssue::test_is_closed tests/test_issues.py::TestIssue::test_issue_137 tests/test_issues.py::TestIssue::test_remove_all_labels tests/test_issues.py::TestIssue::test_remove_label tests/test_issues.py::TestIssue::test_reopen tests/test_issues.py::TestIssue::test_replace_labels tests/test_issues.py::TestIssue::test_repr tests/test_issues.py::TestIssueEvent::test_equality tests/test_issues.py::TestIssueEvent::test_repr
github3/issues/milestone.py AUTHORS.rst
github3/issues/milestone.py AUTHORS.rst