diff --git a/omegaconf/listconfig.py b/omegaconf/listconfig.py
index 6969aab..d2696b5 100644
--- a/omegaconf/listconfig.py
+++ b/omegaconf/listconfig.py
@@ -207,3 +207,10 @@ class ListConfig(Config):
                 return v
 
         return MyItems(self.content)
+
+    def __add__(self, o):
+        # res is sharing this list's parent to allow interpolation to work as expected
+        res = ListConfig(parent=self.__dict__["parent"], content=[])
+        res.extend(self)
+        res.extend(o)
+        return res

consider implementing + operator for ListConfig
diff --git a/tests/test_basic_ops_list.py b/tests/test_basic_ops_list.py
index a97aecb..d2e5a86 100644
--- a/tests/test_basic_ops_list.py
+++ b/tests/test_basic_ops_list.py
@@ -373,3 +373,27 @@ def test_hash():
     assert hash(c1) == hash(c2)
     c2[0] = 20
     assert hash(c1) != hash(c2)
+
+
+@pytest.mark.parametrize(
+    "list1, list2, expected",
+    [
+        ([], [], []),
+        ([1, 2], [3, 4], [1, 2, 3, 4]),
+        (["x", 2, "${0}"], [5, 6, 7], ["x", 2, "x", 5, 6, 7]),
+    ],
+)
+class TestListAdd:
+    def test_list_plus(self, list1, list2, expected):
+        list1 = OmegaConf.create(list1)
+        list2 = OmegaConf.create(list2)
+        expected = OmegaConf.create(expected)
+        ret = list1 + list2
+        assert ret == expected
+
+    def test_list_plus_eq(self, list1, list2, expected):
+        list1 = OmegaConf.create(list1)
+        list2 = OmegaConf.create(list2)
+        expected = OmegaConf.create(expected)
+        list1 += list2
+        assert list1 == expected

pip install -e .[dev]
parse_log_pytest
requirements.txt
pytest
3.6
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
argcomplete==1.12.3
attrs==22.2.0
black==22.8.0
bleach==4.1.0
certifi==2021.5.30
cffi==1.15.1
cfgv==3.3.1
charset-normalizer==2.0.12
click==8.0.4
colorama==0.4.5
colorlog==6.9.0
coverage==6.2
coveralls==3.3.1
cryptography==40.0.2
dataclasses==0.8
distlib==0.3.9
docopt==0.6.2
docutils==0.18.1
filelock==3.4.1
flake8==5.0.4
identify==2.4.4
idna==3.10
importlib-metadata==4.2.0
importlib-resources==5.2.3
iniconfig==1.1.1
jeepney==0.7.1
keyring==23.4.1
mccabe==0.7.0
mypy-extensions==1.0.0
nodeenv==1.6.0
nox==2022.1.7
-e git+https://github.com/omry/omegaconf.git@94d59d0090d4503540e92c1da19781fbe1995061#egg=omegaconf
packaging==21.3
pathspec==0.9.0
pkginfo==1.10.0
platformdirs==2.4.0
pluggy==1.0.0
pre-commit==2.17.0
py==1.11.0
pycodestyle==2.9.1
pycparser==2.21
pyflakes==2.5.0
Pygments==2.14.0
pyparsing==3.1.4
pytest==7.0.1
PyYAML==6.0.1
readme-renderer==34.0
requests==2.27.1
requests-toolbelt==1.0.0
rfc3986==1.5.0
SecretStorage==3.3.3
six==1.17.0
toml==0.10.2
tomli==1.2.3
tqdm==4.64.1
twine==3.8.0
typed-ast==1.5.5
typing_extensions==4.1.1
urllib3==1.26.20
virtualenv==20.16.2
webencodings==0.5.1
zipp==3.6.0

name: omegaconf
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
  - certifi=2021.5.30=py36h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.3=he6710b0_2
  - 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=1.1.1w=h7f8727e_0
  - pip=21.2.2=py36h06a4308_0
  - python=3.6.13=h12debd9_1
  - readline=8.2=h5eee18b_0
  - setuptools=58.0.4=py36h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - wheel=0.37.1=pyhd3eb1b0_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - argcomplete==1.12.3
      - attrs==22.2.0
      - black==22.8.0
      - bleach==4.1.0
      - cffi==1.15.1
      - cfgv==3.3.1
      - charset-normalizer==2.0.12
      - click==8.0.4
      - colorama==0.4.5
      - colorlog==6.9.0
      - coverage==6.2
      - coveralls==3.3.1
      - cryptography==40.0.2
      - dataclasses==0.8
      - distlib==0.3.9
      - docopt==0.6.2
      - docutils==0.18.1
      - filelock==3.4.1
      - flake8==5.0.4
      - identify==2.4.4
      - idna==3.10
      - importlib-metadata==4.2.0
      - importlib-resources==5.2.3
      - iniconfig==1.1.1
      - jeepney==0.7.1
      - keyring==23.4.1
      - mccabe==0.7.0
      - mypy-extensions==1.0.0
      - nodeenv==1.6.0
      - nox==2022.1.7
      - packaging==21.3
      - pathspec==0.9.0
      - pkginfo==1.10.0
      - platformdirs==2.4.0
      - pluggy==1.0.0
      - pre-commit==2.17.0
      - py==1.11.0
      - pycodestyle==2.9.1
      - pycparser==2.21
      - pyflakes==2.5.0
      - pygments==2.14.0
      - pyparsing==3.1.4
      - pytest==7.0.1
      - pyyaml==6.0.1
      - readme-renderer==34.0
      - requests==2.27.1
      - requests-toolbelt==1.0.0
      - rfc3986==1.5.0
      - secretstorage==3.3.3
      - six==1.17.0
      - toml==0.10.2
      - tomli==1.2.3
      - tqdm==4.64.1
      - twine==3.8.0
      - typed-ast==1.5.5
      - typing-extensions==4.1.1
      - urllib3==1.26.20
      - virtualenv==20.16.2
      - webencodings==0.5.1
      - zipp==3.6.0
prefix: /opt/conda/envs/omegaconf

tests/test_basic_ops_list.py::TestListAdd::test_list_plus[list10-list20-expected0] tests/test_basic_ops_list.py::TestListAdd::test_list_plus[list11-list21-expected1] tests/test_basic_ops_list.py::TestListAdd::test_list_plus[list12-list22-expected2] tests/test_basic_ops_list.py::TestListAdd::test_list_plus_eq[list10-list20-expected0] tests/test_basic_ops_list.py::TestListAdd::test_list_plus_eq[list11-list21-expected1] tests/test_basic_ops_list.py::TestListAdd::test_list_plus_eq[list12-list22-expected2]
tests/test_basic_ops_list.py::test_list_value tests/test_basic_ops_list.py::test_list_of_dicts tests/test_basic_ops_list.py::test_pretty_list tests/test_basic_ops_list.py::test_list_get_with_default tests/test_basic_ops_list.py::test_iterate_list tests/test_basic_ops_list.py::test_items_with_interpolation tests/test_basic_ops_list.py::test_list_pop tests/test_basic_ops_list.py::test_in_list tests/test_basic_ops_list.py::test_list_config_with_list tests/test_basic_ops_list.py::test_list_config_with_tuple tests/test_basic_ops_list.py::test_items_on_list tests/test_basic_ops_list.py::test_list_enumerate tests/test_basic_ops_list.py::test_list_delitem tests/test_basic_ops_list.py::test_list_len tests/test_basic_ops_list.py::test_assign_list_in_list tests/test_basic_ops_list.py::test_assign_dict_in_list tests/test_basic_ops_list.py::test_nested_list_assign_illegal_value tests/test_basic_ops_list.py::test_assign_list_in_dict tests/test_basic_ops_list.py::test_list_append tests/test_basic_ops_list.py::test_pretty_without_resolve tests/test_basic_ops_list.py::test_pretty_with_resolve tests/test_basic_ops_list.py::test_index_slice tests/test_basic_ops_list.py::test_index_slice2 tests/test_basic_ops_list.py::test_negative_index tests/test_basic_ops_list.py::test_list_dir tests/test_basic_ops_list.py::test_getattr tests/test_basic_ops_list.py::test_insert tests/test_basic_ops_list.py::test_extend[src0-append0-result0] tests/test_basic_ops_list.py::test_extend[src1-append1-result1] tests/test_basic_ops_list.py::test_extend[src2-append2-result2] tests/test_basic_ops_list.py::test_remove[src0-10-result0-expectation0] tests/test_basic_ops_list.py::test_remove[src1-oops-None-expectation1] tests/test_basic_ops_list.py::test_remove[src2-remove2-result2-expectation2] tests/test_basic_ops_list.py::test_remove[src3-2-result3-expectation3] tests/test_basic_ops_list.py::test_clear[1-src0] tests/test_basic_ops_list.py::test_clear[1-src1] tests/test_basic_ops_list.py::test_clear[1-src2] tests/test_basic_ops_list.py::test_clear[2-src0] tests/test_basic_ops_list.py::test_clear[2-src1] tests/test_basic_ops_list.py::test_clear[2-src2] tests/test_basic_ops_list.py::test_index[src0-20--1-expectation0] tests/test_basic_ops_list.py::test_index[src1-10-0-expectation1] tests/test_basic_ops_list.py::test_index[src2-20-1-expectation2] tests/test_basic_ops_list.py::test_count[src0-10-0] tests/test_basic_ops_list.py::test_count[src1-10-1] tests/test_basic_ops_list.py::test_count[src2-10-2] tests/test_basic_ops_list.py::test_count[src3-None-0] tests/test_basic_ops_list.py::test_copy[src0] tests/test_basic_ops_list.py::test_copy[src1] tests/test_basic_ops_list.py::test_copy[src2] tests/test_basic_ops_list.py::test_sort tests/test_basic_ops_list.py::test_list_eq[l10-l20] tests/test_basic_ops_list.py::test_list_eq[l11-l21] tests/test_basic_ops_list.py::test_list_eq[l12-l22] tests/test_basic_ops_list.py::test_list_eq[l13-l23] tests/test_basic_ops_list.py::test_list_eq[l14-l24] tests/test_basic_ops_list.py::test_list_eq[l15-l25] tests/test_basic_ops_list.py::test_list_eq[l16-l26] tests/test_basic_ops_list.py::test_list_eq_with_interpolation[l10-l20] tests/test_basic_ops_list.py::test_list_not_eq[input10-input20] tests/test_basic_ops_list.py::test_list_not_eq[input11-input21] tests/test_basic_ops_list.py::test_list_not_eq[input12-input22] tests/test_basic_ops_list.py::test_list_not_eq[input13-input23] tests/test_basic_ops_list.py::test_list_not_eq[input14-input24] tests/test_basic_ops_list.py::test_list_not_eq[input15-input25] tests/test_basic_ops_list.py::test_list_not_eq[input16-input26] tests/test_basic_ops_list.py::test_insert_throws_not_changing_list tests/test_basic_ops_list.py::test_append_throws_not_changing_list tests/test_basic_ops_list.py::test_hash
omegaconf/listconfig.py
omegaconf/listconfig.py