diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 18d58d8..cc4ac5d 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -24,7 +24,11 @@ jobs:
       - uses: actions/checkout@v4
       - name: Install LaTeX
         if: runner.os == 'Linux'
-        run: sudo apt-get install texlive-publishers texlive-science cm-super latexmk
+        # `apt-get` waits forever if another process on the runner holds the
+        # dpkg lock, so bound that wait and answer its prompts non-interactively.
+        run: >-
+          sudo apt-get install -y -o DPkg::Lock::Timeout=300
+          texlive-publishers texlive-science cm-super latexmk
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5
         with:
diff --git a/aastex/_aastex.py b/aastex/_aastex.py
index c7f3487..00260b3 100644
--- a/aastex/_aastex.py
+++ b/aastex/_aastex.py
@@ -71,8 +71,14 @@ class Author(pylatex.base_classes.LatexObject):
     name: str
     """Name of the author"""
 
-    affiliation: Affiliation
-    """The organization affiliated with the author"""
+    affiliation: Affiliation | list[Affiliation]
+    """
+    The organization affiliated with the author.
+
+    A list may be given for an author with more than one affiliation, such as
+    someone who has moved since the work was done, in which case the
+    organization where the work was done is usually given first.
+    """
 
     email: None | str = None
     """
@@ -115,12 +121,22 @@ def dumps(self) -> str:
             options=show,
         ).dumps()
 
-        affilation = self.affiliation.dumps()
+        affiliation = "\n".join(a.dumps() for a in self.affiliations)
 
-        result += f"{author}\n{email}\n{affilation}"
+        result += f"{author}\n{email}\n{affiliation}"
 
         return result
 
+    @property
+    def affiliations(self) -> list[Affiliation]:
+        """
+        The organizations affiliated with the author, as a list, whether one
+        or several were given.
+        """
+        if isinstance(self.affiliation, Affiliation):
+            return [self.affiliation]
+        return list(self.affiliation)
+
 
 @dataclasses.dataclass
 class Acronym(pylatex.base_classes.LatexObject):
diff --git a/aastex/_tests/test_aastex.py b/aastex/_tests/test_aastex.py
index 7191d07..d29f940 100644
--- a/aastex/_tests/test_aastex.py
+++ b/aastex/_tests/test_aastex.py
@@ -58,6 +58,13 @@ def test_dumps(self, a: aastex.Affiliation):
             name="John Doe",
             affiliation=aastex.Affiliation("Fancy University"),
         ),
+        aastex.Author(
+            name="Jane Roe",
+            affiliation=[
+                aastex.Affiliation("Fancy University"),
+                aastex.Affiliation("Another Fancy University"),
+            ],
+        ),
     ],
 )
 class TestAuthor:
@@ -65,7 +72,21 @@ def test_name(self, a: aastex.Author):
         assert isinstance(a.name, str)
 
     def test_affiliation(self, a: aastex.Author):
-        assert isinstance(a.affiliation, aastex.Affiliation)
+        result = a.affiliation
+        if not isinstance(result, aastex.Affiliation):
+            assert all(isinstance(r, aastex.Affiliation) for r in result)
+
+    def test_affiliations(self, a: aastex.Author):
+        result = a.affiliations
+        assert isinstance(result, list)
+        assert result
+        assert all(isinstance(r, aastex.Affiliation) for r in result)
+
+        # every affiliation given is rendered
+        dumps = a.dumps()
+        assert dumps.count(r"\affiliation") == len(result)
+        for affiliation in result:
+            assert affiliation.name in dumps
 
     def test_orcid(self, a: aastex.Author):
         result = a.orcid