diff --git a/pyproject.toml b/pyproject.toml
index a5f48bf2..87ba1266 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -66,7 +66,7 @@ optional-dependencies.dev = [
     # but also because having it installed means that ``actionlint-py`` will
     # use it to lint shell commands in GitHub workflow files.
     "shellcheck-py==0.11.0.1",
-    "shfmt-py==3.12.0.2",
+    "shfmt-py==4.0.0",
     "sphinx==9.1.0",
     "sphinx-click==6.2.0",
     "sphinx-copybutton==0.5.2",
diff --git a/uv.lock b/uv.lock
index 88759e3e..86895d38 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1812,9 +1812,16 @@ wheels = [
 
 [[package]]
 name = "shfmt-py"
-version = "3.12.0.2"
+version = "4.0.0"
 source = { registry = "https://pypi.org/simple" }
-sdist = { url = "https://files.pythonhosted.org/packages/af/d9/a1ea26749bd19467e9fbfe7b34e6c8df517e01de4028a45b954eebe8c03b/shfmt_py-3.12.0.2.tar.gz", hash = "sha256:6a0dc675b37d000eb236609cf15aedd9e7a538927ea02c57b617908b6f237e9c", size = 4467, upload-time = "2025-07-08T06:54:40.396Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/06/d5/c2ad5c6593a34da7344cf39bde65763e8cda752589074ba1619e55b317ad/shfmt_py-4.0.0.tar.gz", hash = "sha256:1e5fdacf40aabaa77a97639d52a6220df0893b46658d82b7f136f4e66e2b2fb0", size = 11947, upload-time = "2026-05-13T09:25:50.153Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/5a/1d/8f72824e2a0e06dc0bc2687baacaba0573be7d2e93c01d1e895fddd8c13e/shfmt_py-4.0.0-py2.py3-none-macosx_10_9_x86_64.whl", hash = "sha256:75a4919a03fb3bcff9795e3cc7b971e37e74905654d2f11605001cab42e5f92f", size = 1343695, upload-time = "2026-05-13T09:25:42.969Z" },
+    { url = "https://files.pythonhosted.org/packages/a8/82/9564a2c2a76fbec94db1b3a3c37a9a1d00e7eafca2cdd2e0d19082618d7e/shfmt_py-4.0.0-py2.py3-none-macosx_11_0_arm64.whl", hash = "sha256:bb3d236163ff39c7790953e069938caf247e7646399f7a059f00f65d4e6916d6", size = 1237947, upload-time = "2026-05-13T09:25:44.767Z" },
+    { url = "https://files.pythonhosted.org/packages/9a/a9/6fce944efa530db941edd11388d70dc7384aaf12169a3b0847b6a6c987b0/shfmt_py-4.0.0-py2.py3-none-manylinux2014_aarch64.whl", hash = "sha256:4701336c3cb5f3959a5e85481b14f02054ea094b3c666f3d04649bbe10de3c25", size = 1218771, upload-time = "2026-05-13T09:25:46.225Z" },
+    { url = "https://files.pythonhosted.org/packages/64/43/e3965a25bb39555f2791c6860214f62b6f976f9ac7e9786073364bcdd9a6/shfmt_py-4.0.0-py2.py3-none-manylinux2014_x86_64.whl", hash = "sha256:e57877abe0177a9da7bbb5390fe7e96aa19b00958189a025634039aef8834d44", size = 1350939, upload-time = "2026-05-13T09:25:47.584Z" },
+    { url = "https://files.pythonhosted.org/packages/95/20/db2430d9262d2cffadcad2b330441e13031f1ab849ec069659edb7f23257/shfmt_py-4.0.0-py2.py3-none-win_amd64.whl", hash = "sha256:bd4f3d36264d4ba8b014ff73e5e702aaa2345845c021f563480128de3705135b", size = 1427721, upload-time = "2026-05-13T09:25:48.865Z" },
+]
 
 [[package]]
 name = "six"
@@ -2484,7 +2491,7 @@ requires-dist = [
     { name = "ruff", marker = "extra == 'dev'", specifier = "==0.15.12" },
     { name = "setuptools-scm", marker = "extra == 'dev'", specifier = "==10.0.5" },
     { name = "shellcheck-py", marker = "extra == 'dev'", specifier = "==0.11.0.1" },
-    { name = "shfmt-py", marker = "extra == 'dev'", specifier = "==3.12.0.2" },
+    { name = "shfmt-py", marker = "extra == 'dev'", specifier = "==4.0.0" },
     { name = "sphinx", marker = "extra == 'dev'", specifier = "==9.1.0" },
     { name = "sphinx-click", marker = "extra == 'dev'", specifier = "==6.2.0" },
     { name = "sphinx-copybutton", marker = "extra == 'dev'", specifier = "==0.5.2" },