diff --git a/end_to_end_tests/golden-record/pyproject.toml b/end_to_end_tests/golden-record/pyproject.toml
index 2eed9cffe..fe727eb0c 100644
--- a/end_to_end_tests/golden-record/pyproject.toml
+++ b/end_to_end_tests/golden-record/pyproject.toml
@@ -12,7 +12,7 @@ include = ["CHANGELOG.md", "my_test_api_client/py.typed"]
 
 [tool.poetry.dependencies]
 python = "^3.8"
-httpx = ">=0.20.0,<0.27.0"
+httpx = ">=0.20.0,<0.28.0"
 attrs = ">=21.3.0"
 python-dateutil = "^2.8.0"
 
diff --git a/end_to_end_tests/metadata_snapshots/pdm.pyproject.toml b/end_to_end_tests/metadata_snapshots/pdm.pyproject.toml
index 0cc547a17..cb818d5f1 100644
--- a/end_to_end_tests/metadata_snapshots/pdm.pyproject.toml
+++ b/end_to_end_tests/metadata_snapshots/pdm.pyproject.toml
@@ -6,7 +6,7 @@ authors = []
 readme = "README.md"
 requires-python = ">=3.8,<4.0"
 dependencies = [
-    "httpx>=0.20.0,<0.27.0",
+    "httpx>=0.20.0,<0.28.0",
     "attrs>=21.3.0",
     "python-dateutil>=2.8.0",
 ]
diff --git a/end_to_end_tests/metadata_snapshots/poetry.pyproject.toml b/end_to_end_tests/metadata_snapshots/poetry.pyproject.toml
index 1db67cd2b..f1fe4a2f2 100644
--- a/end_to_end_tests/metadata_snapshots/poetry.pyproject.toml
+++ b/end_to_end_tests/metadata_snapshots/poetry.pyproject.toml
@@ -12,7 +12,7 @@ include = ["CHANGELOG.md", "test_3_1_features_client/py.typed"]
 
 [tool.poetry.dependencies]
 python = "^3.8"
-httpx = ">=0.20.0,<0.27.0"
+httpx = ">=0.20.0,<0.28.0"
 attrs = ">=21.3.0"
 python-dateutil = "^2.8.0"
 
diff --git a/end_to_end_tests/metadata_snapshots/setup.py b/end_to_end_tests/metadata_snapshots/setup.py
index 6826d63a3..6350b8c4c 100644
--- a/end_to_end_tests/metadata_snapshots/setup.py
+++ b/end_to_end_tests/metadata_snapshots/setup.py
@@ -13,6 +13,6 @@
     long_description_content_type="text/markdown",
     packages=find_packages(),
     python_requires=">=3.8, <4",
-    install_requires=["httpx >= 0.20.0, < 0.27.0", "attrs >= 21.3.0", "python-dateutil >= 2.8.0, < 3"],
+    install_requires=["httpx >= 0.20.0, < 0.28.0", "attrs >= 21.3.0", "python-dateutil >= 2.8.0, < 3"],
     package_data={"test_3_1_features_client": ["py.typed"]},
 )
diff --git a/end_to_end_tests/test-3-1-golden-record/pyproject.toml b/end_to_end_tests/test-3-1-golden-record/pyproject.toml
index 1db67cd2b..f1fe4a2f2 100644
--- a/end_to_end_tests/test-3-1-golden-record/pyproject.toml
+++ b/end_to_end_tests/test-3-1-golden-record/pyproject.toml
@@ -12,7 +12,7 @@ include = ["CHANGELOG.md", "test_3_1_features_client/py.typed"]
 
 [tool.poetry.dependencies]
 python = "^3.8"
-httpx = ">=0.20.0,<0.27.0"
+httpx = ">=0.20.0,<0.28.0"
 attrs = ">=21.3.0"
 python-dateutil = "^2.8.0"
 
diff --git a/integration-tests/pdm.lock b/integration-tests/pdm.lock
index d11f26c85..01f3e592f 100644
--- a/integration-tests/pdm.lock
+++ b/integration-tests/pdm.lock
@@ -5,7 +5,7 @@
 groups = ["default", "dev"]
 strategy = ["cross_platform", "inherit_metadata"]
 lock_version = "4.4.1"
-content_hash = "sha256:326f8a17184de225443b8eb5ed976e16e9d3f830d8d0fc58b3c7968805ef8d84"
+content_hash = "sha256:21f2d31fc91486810f21163e5ce7d73ebd8265f44bbef79d817d14c61d97c34a"
 
 [[package]]
 name = "anyio"
@@ -98,7 +98,7 @@ files = [
 
 [[package]]
 name = "httpx"
-version = "0.26.0"
+version = "0.27.0"
 requires_python = ">=3.8"
 summary = "The next generation HTTP client."
 groups = ["default"]
@@ -110,8 +110,8 @@ dependencies = [
     "sniffio",
 ]
 files = [
-    {file = "httpx-0.26.0-py3-none-any.whl", hash = "sha256:8915f5a3627c4d47b73e8202457cb28f1266982d1159bd5779d86a80c0eab1cd"},
-    {file = "httpx-0.26.0.tar.gz", hash = "sha256:451b55c30d5185ea6b23c2c793abf9bb237d2a7dfb901ced6ff69ad37ec1dfaf"},
+    {file = "httpx-0.27.0-py3-none-any.whl", hash = "sha256:71d5465162c13681bff01ad59b2cc68dd838ea1f10e51574bac27103f00c91a5"},
+    {file = "httpx-0.27.0.tar.gz", hash = "sha256:a0cb88a46f32dc874e04ee956e4c2764aba2aa228f650b06788ba6bda2962ab5"},
 ]
 
 [[package]]
diff --git a/integration-tests/pyproject.toml b/integration-tests/pyproject.toml
index c2cbd3226..21a5b2877 100644
--- a/integration-tests/pyproject.toml
+++ b/integration-tests/pyproject.toml
@@ -5,7 +5,7 @@ description = "A client library for accessing OpenAPI Test Server"
 authors = []
 readme = "README.md"
 dependencies = [
-    "httpx>=0.20.0,<0.27.0",
+    "httpx>=0.20.0,<0.28.0",
     "attrs>=21.3.0",
     "python-dateutil>=2.8.0",
 ]
diff --git a/openapi_python_client/templates/pyproject.toml.jinja b/openapi_python_client/templates/pyproject.toml.jinja
index fced0e8bd..f836bff19 100644
--- a/openapi_python_client/templates/pyproject.toml.jinja
+++ b/openapi_python_client/templates/pyproject.toml.jinja
@@ -19,7 +19,7 @@ include = ["CHANGELOG.md", "{{ package_name }}/py.typed"]
 
 {% if pdm %}
 dependencies = [
-    "httpx>=0.20.0,<0.27.0",
+    "httpx>=0.20.0,<0.28.0",
     "attrs>=21.3.0",
     "python-dateutil>=2.8.0",
 ]
@@ -31,7 +31,7 @@ package-type = "library"
 
 [tool.poetry.dependencies]
 python = "^3.8"
-httpx = ">=0.20.0,<0.27.0"
+httpx = ">=0.20.0,<0.28.0"
 attrs = ">=21.3.0"
 python-dateutil = "^2.8.0"
 {% endif %}
diff --git a/openapi_python_client/templates/setup.py.jinja b/openapi_python_client/templates/setup.py.jinja
index b2290bd12..87c0cc063 100644
--- a/openapi_python_client/templates/setup.py.jinja
+++ b/openapi_python_client/templates/setup.py.jinja
@@ -13,6 +13,6 @@ setup(
     long_description_content_type="text/markdown",
     packages=find_packages(),
     python_requires=">=3.8, <4",
-    install_requires=["httpx >= 0.20.0, < 0.27.0", "attrs >= 21.3.0", "python-dateutil >= 2.8.0, < 3"],
+    install_requires=["httpx >= 0.20.0, < 0.28.0", "attrs >= 21.3.0", "python-dateutil >= 2.8.0, < 3"],
     package_data={"{{ package_name }}": ["py.typed"]},
 )
diff --git a/pdm.lock b/pdm.lock
index 20490f470..e9bdfd4e7 100644
--- a/pdm.lock
+++ b/pdm.lock
@@ -5,7 +5,7 @@
 groups = ["default", "dev"]
 strategy = ["cross_platform", "inherit_metadata"]
 lock_version = "4.4.1"
-content_hash = "sha256:95755a37ee3e6a924fa539d7bf00ac5255bb5e3649405afd078ad8a8e8c85002"
+content_hash = "sha256:f1003f6101234e70c1a5fc95bdc014ac2e0b48c1dee75eb0624140dc6c4ea6f6"
 
 [[package]]
 name = "annotated-types"
@@ -352,7 +352,7 @@ files = [
 
 [[package]]
 name = "httpx"
-version = "0.26.0"
+version = "0.27.0"
 requires_python = ">=3.8"
 summary = "The next generation HTTP client."
 groups = ["default"]
@@ -364,8 +364,8 @@ dependencies = [
     "sniffio",
 ]
 files = [
-    {file = "httpx-0.26.0-py3-none-any.whl", hash = "sha256:8915f5a3627c4d47b73e8202457cb28f1266982d1159bd5779d86a80c0eab1cd"},
-    {file = "httpx-0.26.0.tar.gz", hash = "sha256:451b55c30d5185ea6b23c2c793abf9bb237d2a7dfb901ced6ff69ad37ec1dfaf"},
+    {file = "httpx-0.27.0-py3-none-any.whl", hash = "sha256:71d5465162c13681bff01ad59b2cc68dd838ea1f10e51574bac27103f00c91a5"},
+    {file = "httpx-0.27.0.tar.gz", hash = "sha256:a0cb88a46f32dc874e04ee956e4c2764aba2aa228f650b06788ba6bda2962ab5"},
 ]
 
 [[package]]
diff --git a/pyproject.toml b/pyproject.toml
index ce36e2d09..8b4d2cc29 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,7 +12,7 @@ dependencies = [
     "pydantic>=2.1.1,<3.0.0",
     "attrs>=21.3.0",
     "python-dateutil>=2.8.1,<3.0.0",
-    "httpx>=0.20.0,<0.27.0",
+    "httpx>=0.20.0,<0.28.0",
     "PyYAML>=6.0,<7.0",
     "ruff>=0.1.2,<1.0.0",
     "typing-extensions>=4.8.0,<5.0.0",