diff --git a/src/tox_uv/_run_lock.py b/src/tox_uv/_run_lock.py
index 374737b..bd4cd26 100644
--- a/src/tox_uv/_run_lock.py
+++ b/src/tox_uv/_run_lock.py
@@ -60,7 +60,7 @@ def register_config(self) -> None:
 
     def _setup_env(self) -> None:
         super()._setup_env()
-        cmd = ["uv", "sync", "--frozen"]
+        cmd = ["uv", "sync", "--frozen", "--python-preference=system"]
         for extra in cast("set[str]", sorted(self.conf["extras"])):
             cmd.extend(("--extra", extra))
         if not self.conf["with_dev"]:
diff --git a/tests/test_tox_uv_lock.py b/tests/test_tox_uv_lock.py
index 1539d88..73becdf 100644
--- a/tests/test_tox_uv_lock.py
+++ b/tests/test_tox_uv_lock.py
@@ -33,7 +33,7 @@ def test_uv_lock_list_dependencies_command(tox_project: ToxProjectCreator) -> No
             "venv",
             [uv, "venv", "-p", sys.executable, "--allow-existing", "-v", str(project.path / ".tox" / "py")],
         ),
-        ("py", "uv-sync", ["uv", "sync", "--frozen", "--extra", "dev", "--extra", "type", "--no-dev", "-v"]),
+        ("py", "uv-sync", ["uv", "sync", "--frozen", "--python-preference=system", "--extra", "dev", "--extra", "type", "--no-dev", "-v"]),
         ("py", "freeze", [uv, "--color", "never", "pip", "freeze"]),
         ("py", "commands[0]", ["python", "hello"]),
     ]
@@ -65,7 +65,7 @@ def test_uv_lock_command(tox_project: ToxProjectCreator, verbose: str) -> None:
             "venv",
             [uv, "venv", "-p", sys.executable, "--allow-existing", *v_args, str(project.path / ".tox" / "py")],
         ),
-        ("py", "uv-sync", ["uv", "sync", "--frozen", "--extra", "dev", "--extra", "type", "--no-dev", *v_args]),
+        ("py", "uv-sync", ["uv", "sync", "--frozen", "--python-preference=system","--extra", "dev", "--extra", "type", "--no-dev", *v_args]),
         ("py", "commands[0]", ["python", "hello"]),
     ]
     assert calls == expected
@@ -93,7 +93,7 @@ def test_uv_lock_with_dev(tox_project: ToxProjectCreator) -> None:
             "venv",
             [uv, "venv", "-p", sys.executable, "--allow-existing", "-v", str(project.path / ".tox" / "py")],
         ),
-        ("py", "uv-sync", ["uv", "sync", "--frozen", "-v"]),
+        ("py", "uv-sync", ["uv", "sync", "--frozen", "--python-preference=system", "-v"]),
     ]
     assert calls == expected
 
@@ -126,7 +126,7 @@ def test_uv_lock_with_install_pkg(tox_project: ToxProjectCreator, name: str) ->
             "venv",
             [uv, "venv", "-p", sys.executable, "--allow-existing", "-v", str(project.path / ".tox" / "py")],
         ),
-        ("py", "uv-sync", ["uv", "sync", "--frozen", "--no-dev", "--no-install-project", "-v"]),
+        ("py", "uv-sync", ["uv", "sync", "--frozen", '--python-preference=system', "--no-dev", "--no-install-project", "-v"]),
         (
             "py",
             "install_external",
@@ -162,7 +162,7 @@ def test_uv_sync_extra_flags(tox_project: ToxProjectCreator) -> None:
         (
             "py",
             "uv-sync",
-            ["uv", "sync", "--frozen", "--no-editable", "--inexact"],
+            ["uv", "sync", "--frozen", '--python-preference=system', "--no-editable", "--inexact"],
         ),
         ("py", "commands[0]", ["python", "hello"]),
     ]
@@ -195,7 +195,7 @@ def test_uv_sync_extra_flags_toml(tox_project: ToxProjectCreator) -> None:
         (
             "py",
             "uv-sync",
-            ["uv", "sync", "--frozen", "--no-editable", "--inexact"],
+            ["uv", "sync", "--frozen", "--python-preference=system", "--no-editable", "--inexact"],
         ),
         ("py", "commands[0]", ["python", "hello"]),
     ]
@@ -228,7 +228,7 @@ def test_uv_sync_dependency_groups(tox_project: ToxProjectCreator) -> None:
         (
             "py",
             "uv-sync",
-            ["uv", "sync", "--frozen", "--group", "test", "--group", "type"],
+            ["uv", "sync", "--frozen", '--python-preference=system', "--group", "test", "--group", "type"],
         ),
         ("py", "commands[0]", ["python", "hello"]),
     ]