diff --git a/tests/test_gc.py b/tests/test_gc.py
index a5dcc90..ac1001b 100644
--- a/tests/test_gc.py
+++ b/tests/test_gc.py
@@ -8,6 +8,8 @@ import xfstestsdb.xunit.gc
 import tests.xunit
 
 
+@unittest.mock.patch("xfstestsdb.sqlite.Connection.vacuum")
+@unittest.mock.patch("sys.stdout", new_callable=io.StringIO)
 class TestGC(unittest.TestCase):
     """Tests the `xfstestsdb xunit gc` command."""
 
@@ -31,24 +33,26 @@ class TestGC(unittest.TestCase):
         mock_stdout.seek(0)
         mock_stdout.truncate(0)
 
-    def test_init(self):
+    def test_init(self, mock_stdout: io.StringIO,
+                  mock_vacuum: unittest.mock.Mock):
         """Check that the gc command was set up properly."""
         self.assertIsInstance(self.gc, xfstestsdb.commands.Command)
         self.assertIsInstance(self.gc, xfstestsdb.xunit.gc.Command)
         self.assertEqual(self.xunit.subparser.choices["gc"],
                          self.gc.parser)
 
-    @unittest.mock.patch("sys.stdout", new_callable=io.StringIO)
-    def test_gc_empty(self, mock_stdout: io.StringIO):
+    def test_gc_empty(self, mock_stdout: io.StringIO,
+                      mock_vacuum: unittest.mock.Mock):
         """Test garbage collecting an empty database."""
         cur = self.xfstestsdb.sql("SELECT runid FROM xfstests_gc_runs")
         self.assertListEqual([row['runid'] for row in cur.fetchall()], [])
 
         self.xfstestsdb.run(["gc"])
         self.assertEqual(mock_stdout.getvalue(), "")
+        mock_vacuum.assert_not_called()
 
-    @unittest.mock.patch("sys.stdout", new_callable=io.StringIO)
-    def test_gc_no_testcases(self, mock_stdout: io.StringIO):
+    def test_gc_no_testcases(self, mock_stdout: io.StringIO,
+                             mock_vacuum: unittest.mock.Mock):
         """Test garbage collecting runs with no testcases."""
         self.setup_runs(mock_stdout)
 
@@ -61,9 +65,10 @@ class TestGC(unittest.TestCase):
 
         cur = self.xfstestsdb.sql("SELECT runid FROM xfstests_runs")
         self.assertListEqual([row['runid'] for row in cur.fetchall()], [1])
+        mock_vacuum.assert_called()
 
-    @unittest.mock.patch("sys.stdout", new_callable=io.StringIO)
-    def test_gc_expired(self, mock_stdout: io.StringIO):
+    def test_gc_expired(self, mock_stdout: io.StringIO,
+                        mock_vacuum: unittest.mock.Mock):
         """Test garbage collecting old runs."""
         self.setup_runs(mock_stdout)
         self.xfstestsdb.run(["xunit", "read", "2", str(tests.xunit.XUNIT_1)])
@@ -87,9 +92,10 @@ class TestGC(unittest.TestCase):
 
         cur = self.xfstestsdb.sql("SELECT runid FROM xfstests_runs")
         self.assertListEqual([row['runid'] for row in cur.fetchall()], [2])
+        mock_vacuum.assert_called()
 
-    @unittest.mock.patch("sys.stdout", new_callable=io.StringIO)
-    def test_gc_expired_tagged(self, mock_stdout: io.StringIO):
+    def test_gc_expired_tagged(self, mock_stdout: io.StringIO,
+                               mock_vacuum: unittest.mock.Mock):
         """Test that we don't garbage collect expired runs that are tagged."""
         self.setup_runs(mock_stdout)
         self.xfstestsdb.run(["xunit", "read", "2", str(tests.xunit.XUNIT_1)])
@@ -109,9 +115,10 @@ class TestGC(unittest.TestCase):
 
         cur = self.xfstestsdb.sql("SELECT runid FROM xfstests_runs")
         self.assertListEqual([row['runid'] for row in cur.fetchall()], [1])
+        mock_vacuum.assert_called()
 
-    @unittest.mock.patch("sys.stdout", new_callable=io.StringIO)
-    def test_gc_dry_run(self, mock_stdout: io.StringIO):
+    def test_gc_dry_run(self, mock_stdout: io.StringIO,
+                        mock_vacuum: unittest.mock.Mock):
         """Test garbage collecting with the --dry-run option."""
         self.setup_runs(mock_stdout)
         self.xfstestsdb.run(["gc", "--dry-run"])
@@ -121,3 +128,4 @@ class TestGC(unittest.TestCase):
         cur = self.xfstestsdb.sql("SELECT runid FROM xfstests_runs")
         self.assertListEqual([row['runid'] for row in cur.fetchall()],
                              [1, 2, 3])
+        mock_vacuum.assert_not_called()
diff --git a/tests/test_sqlite.py b/tests/test_sqlite.py
index 6adb940..1b54754 100644
--- a/tests/test_sqlite.py
+++ b/tests/test_sqlite.py
@@ -114,6 +114,10 @@ class TestConnection(unittest.TestCase):
         with self.assertRaises(sqlite3.OperationalError):
             self.sql("SELECT COUNT(*) FROM other_table")
 
+    def test_vacuum(self):
+        """Test vacuuming the database."""
+        self.assertIsInstance(self.sql.vacuum(), sqlite3.Cursor)
+
     def test_close(self):
         """Check closing the connection."""
         self.sql.close()
diff --git a/xfstestsdb/gc.py b/xfstestsdb/gc.py
index 450ec8e..827fb61 100644
--- a/xfstestsdb/gc.py
+++ b/xfstestsdb/gc.py
@@ -25,3 +25,10 @@ class Command(commands.Command):
             if not args.dry_run:
                 self.sql("DELETE FROM xfstests_runs WHERE runid=?", runid)
             print(f"run #{runid} {how} deleted")
+
+        args.need_vacuum = len(rows) > 0
+
+    def do_done(self, args: argparse.Namespace) -> None:
+        """Vacuum the database after deleting."""
+        if args.need_vacuum and not args.dry_run:
+            self.sql.vacuum()
diff --git a/xfstestsdb/sqlite.py b/xfstestsdb/sqlite.py
index 52d881d..b02b3e8 100644
--- a/xfstestsdb/sqlite.py
+++ b/xfstestsdb/sqlite.py
@@ -76,3 +76,7 @@ class Connection:
                 cur = self.sql.executescript(f.read())
                 self.sql.commit()
                 return cur
+
+    def vacuum(self) -> sqlite3.Cursor | None:
+        """Vacuum the database."""
+        return self.sql.execute("VACUUM")