diff --git a/.ci/ansible_tests.py b/.ci/ansible_tests.py
index 01a012f5..0d67c3b2 100755
--- a/.ci/ansible_tests.py
+++ b/.ci/ansible_tests.py
@@ -14,7 +14,8 @@ import ci_lib
 
 TEMPLATES_DIR = os.path.join(ci_lib.GIT_ROOT, 'tests/ansible/templates')
 TESTS_DIR = os.path.join(ci_lib.GIT_ROOT, 'tests/ansible')
-HOSTS_DIR = os.path.join(ci_lib.TMP, 'hosts')
+TMP = ci_lib.TempDir(prefix='mitogen_ci_ansible')
+TMP_HOSTS_DIR = os.path.join(TMP.path, 'hosts')
 
 
 def pause_if_interactive():
@@ -43,10 +44,10 @@ with ci_lib.Fold('job_setup'):
     os.chmod(ci_lib.TESTS_SSH_PRIVATE_KEY_FILE, int('0600', 8))
     os.chdir(TESTS_DIR)
 
-    ci_lib.run("mkdir %s", HOSTS_DIR)
+    os.mkdir(TMP_HOSTS_DIR)
     for path in glob.glob(TESTS_DIR + '/hosts/*'):
         if not path.endswith('default.hosts'):
-            ci_lib.run("ln -s %s %s", path, HOSTS_DIR)
+            os.symlink(path, os.path.join(TMP_HOSTS_DIR, os.path.basename(path)))
 
     distros = collections.defaultdict(list)
     families = collections.defaultdict(list)
@@ -60,7 +61,7 @@ with ci_lib.Fold('job_setup'):
         trim_blocks=True,  # Remove first newline after a block
     )
     inventory_template = jinja_env.get_template('test-targets.j2')
-    inventory_path = os.path.join(HOSTS_DIR, 'target')
+    inventory_path = os.path.join(TMP_HOSTS_DIR, 'test-targets.ini')
 
     with open(inventory_path, 'w') as fp:
         fp.write(inventory_template.render(
@@ -75,7 +76,8 @@ with ci_lib.Fold('ansible'):
     playbook = os.environ.get('PLAYBOOK', 'all.yml')
     try:
         ci_lib.run('./run_ansible_playbook.py %s -i "%s" %s',
-            playbook, HOSTS_DIR, ' '.join(sys.argv[1:]))
+            playbook, TMP_HOSTS_DIR, ' '.join(sys.argv[1:]),
+        )
     except:
         pause_if_interactive()
         raise
diff --git a/.ci/ci_lib.py b/.ci/ci_lib.py
index b0c9c04a..b37472a2 100644
--- a/.ci/ci_lib.py
+++ b/.ci/ci_lib.py
@@ -179,8 +179,8 @@ def exists_in_path(progname):
 
 
 class TempDir(object):
-    def __init__(self):
-        self.path = tempfile.mkdtemp(prefix='mitogen_ci_lib')
+    def __init__(self, prefix='mitogen_ci_lib'):
+        self.path = tempfile.mkdtemp(prefix=prefix)
         atexit.register(self.destroy)
 
     def destroy(self, rmtree=shutil.rmtree):
@@ -193,9 +193,6 @@ class Fold(object):
     def __exit__(self, _1, _2, _3): pass
 
 
-TMP = TempDir().path
-
-
 os.environ['PYTHONDONTWRITEBYTECODE'] = 'x'
 os.environ['PYTHONPATH'] = '%s:%s' % (
     os.environ.get('PYTHONPATH', ''),
diff --git a/.ci/debops_common_tests.py b/.ci/debops_common_tests.py
index b9b0030c..6fd50124 100755
--- a/.ci/debops_common_tests.py
+++ b/.ci/debops_common_tests.py
@@ -6,7 +6,8 @@ import sys
 import ci_lib
 
 
-project_dir = os.path.join(ci_lib.TMP, 'project')
+TMP = ci_lib.TempDir(prefix='mitogen_ci_debops')
+project_dir = os.path.join(TMP.path, 'project')
 vars_path = 'ansible/inventory/group_vars/debops_all_hosts.yml'
 inventory_path = 'ansible/inventory/hosts'
 docker_hostname = ci_lib.get_docker_hostname()
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 1fbee883..ba4a608b 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -25,6 +25,7 @@ In progress (unreleased)
 * :gh:issue:`1238` packaging: Avoid :py:mod:`ast`, requires Python = 2.6
 * :gh:issue:`1118` CI: Statically specify test usernames and group names
 * :gh:issue:`1118` CI: Don't copy SSH private key to temporary dir
+* :gh:issue:`1118` CI: Don't share temporary directory between test groupings
 
 
 v0.3.22 (2025-02-04)