diff --git a/main.go b/main.go
index b7ad0b8..52e0b61 100644
--- a/main.go
+++ b/main.go
@@ -327,6 +327,7 @@ func licenseHeader(path string, tmpl *template.Template, data licenseData) ([]by
 		".ex", ".exs",
 		".fpp",
 		".graphql",
+		".ini",
 		".jl",
 		".nix",
 		".pl",
diff --git a/main_test.go b/main_test.go
index 5aa7648..d93a884 100644
--- a/main_test.go
+++ b/main_test.go
@@ -352,6 +352,7 @@ func TestLicenseHeader(t *testing.T) {
 				"f.ex", "f.exs",
 				"f.graphql",
 				"f.jl",
+				"f.ini",
 				"f.nix",
 				"f.pl",
 				"f.pp",
diff --git a/testdata/expected/file.ini b/testdata/expected/file.ini
new file mode 100644
index 0000000..09950cf
--- /dev/null
+++ b/testdata/expected/file.ini
@@ -0,0 +1,24 @@
+# Copyright 2018 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+[pytest]
+addopts = --doctest-glob="*.md" --doctest-modules --numprocesses auto --random-order --strict-config --strict-markers
+empty_parameter_set_mark = xfail
+xfail_strict=true
+markers =
+    slow: mark test as slow to run
+    integration: mark test as an integration test
+    unit: mark test as a unit test
+    regression: mark test as a regression test
+    flaky: mark test as flaky, may need to be retried
diff --git a/testdata/initial/file.ini b/testdata/initial/file.ini
new file mode 100644
index 0000000..92c92cd
--- /dev/null
+++ b/testdata/initial/file.ini
@@ -0,0 +1,10 @@
+[pytest]
+addopts = --doctest-glob="*.md" --doctest-modules --numprocesses auto --random-order --strict-config --strict-markers
+empty_parameter_set_mark = xfail
+xfail_strict=true
+markers =
+    slow: mark test as slow to run
+    integration: mark test as an integration test
+    unit: mark test as a unit test
+    regression: mark test as a regression test
+    flaky: mark test as flaky, may need to be retried