diff --git a/cibuildwheel/__main__.py b/cibuildwheel/__main__.py
index 17fdf393..a624baa9 100644
--- a/cibuildwheel/__main__.py
+++ b/cibuildwheel/__main__.py
@@ -134,7 +134,7 @@ def main() -> None:
 
     dependency_versions = get_option_from_environment('CIBW_DEPENDENCY_VERSIONS', platform=platform, default='pinned')
     if dependency_versions == 'pinned':
-        dependency_constraints = DependencyConstraints.with_defaults()  # type: Optional[DependencyConstraints]
+        dependency_constraints: Optional[DependencyConstraints] = DependencyConstraints.with_defaults()
     elif dependency_versions == 'latest':
         dependency_constraints = None
     else:
@@ -169,7 +169,7 @@ def main() -> None:
         print_build_identifiers(platform, build_selector)
         exit(0)
 
-    manylinux_images = None  # type: Optional[Dict[str, str]]
+    manylinux_images: Optional[Dict[str, str]] = None
     if platform == 'linux':
         pinned_docker_images_file = os.path.join(
             os.path.dirname(__file__), 'resources', 'pinned_docker_images.cfg'
@@ -287,14 +287,13 @@ def print_preamble(platform: str, build_options: BuildOptions) -> None:
 
 
 def print_build_identifiers(platform: str, build_selector: BuildSelector) -> None:
+    python_configurations: List[Any] = []
     if platform == 'linux':
-        python_configurations = cibuildwheel.linux.get_python_configurations(build_selector)  # type: List[Any]
+        python_configurations = cibuildwheel.linux.get_python_configurations(build_selector)
     elif platform == 'windows':
         python_configurations = cibuildwheel.windows.get_python_configurations(build_selector)
     elif platform == 'macos':
         python_configurations = cibuildwheel.macos.get_python_configurations(build_selector)
-    else:
-        python_configurations = []
 
     for config in python_configurations:
         print(config.identifier)
diff --git a/cibuildwheel/bashlex_eval.py b/cibuildwheel/bashlex_eval.py
index a10fe832..3101089d 100644
--- a/cibuildwheel/bashlex_eval.py
+++ b/cibuildwheel/bashlex_eval.py
@@ -5,9 +5,10 @@ from typing import Dict, List, NamedTuple, Optional
 
 import bashlex  # type: ignore
 
-NodeExecutionContext = NamedTuple('NodeExecutionContext',
-                                  [('environment', Dict[str, str]),
-                                   ('input', str)])
+
+class NodeExecutionContext(NamedTuple):
+    environment: Dict[str, str]
+    input: str
 
 
 def evaluate(value: str, environment: Dict[str, str]) -> str:
@@ -44,7 +45,7 @@ def evaluate_word_node(node: bashlex.ast.node, context: NodeExecutionContext) ->
     word_start = node.pos[0]
     word_end = node.pos[1]
     word_string = context.input[word_start:word_end]
-    letters = list(word_string)  # type: List[Optional[str]]
+    letters: List[Optional[str]] = list(word_string)
 
     for part in node.parts:
         part_start = part.pos[0] - word_start
diff --git a/cibuildwheel/linux.py b/cibuildwheel/linux.py
index 38ecf943..2ceaf8f1 100644
--- a/cibuildwheel/linux.py
+++ b/cibuildwheel/linux.py
@@ -43,7 +43,10 @@ def matches_platform(identifier: str) -> bool:
     return False
 
 
-PythonConfiguration = NamedTuple('PythonConfiguration', [('version', str), ('identifier', str), ('path', str)])
+class PythonConfiguration(NamedTuple):
+    version: str
+    identifier: str
+    path: str
 
 
 def get_python_configurations(build_selector: Callable[[str], bool]) -> List[PythonConfiguration]:
diff --git a/cibuildwheel/macos.py b/cibuildwheel/macos.py
index 911d9978..e2b18b88 100644
--- a/cibuildwheel/macos.py
+++ b/cibuildwheel/macos.py
@@ -28,7 +28,10 @@ def call(args: Union[str, List[str]], env: Optional[Dict[str, str]] = None, cwd:
     return subprocess.check_call(args, env=env, cwd=cwd, shell=shell)
 
 
-PythonConfiguration = NamedTuple('PythonConfiguration', [('version', str), ('identifier', str), ('url', str)])
+class PythonConfiguration(NamedTuple):
+    version: str
+    identifier: str
+    url: str
 
 
 def get_python_configurations(build_selector: Callable[[str], bool]) -> List[PythonConfiguration]:
diff --git a/cibuildwheel/util.py b/cibuildwheel/util.py
index 33e45adf..c466af3f 100644
--- a/cibuildwheel/util.py
+++ b/cibuildwheel/util.py
@@ -110,26 +110,21 @@ class DependencyConstraints:
             return self.base_file_path
 
 
-BuildOptions = NamedTuple("BuildOptions", [
-    ("package_dir", str),
-    ("output_dir", str),
-    ("test_command", Optional[str]),
-    ("test_requires", List[str]),
-    ("test_extras", str),
-    ("before_build", Optional[str]),
-    ("build_verbosity", int),
-    ("build_selector", BuildSelector),
-    ("repair_command", str),
-    ("environment", ParsedEnvironment),
-    ("before_test", str),
-    ("dependency_constraints", Optional[DependencyConstraints]),
-    ("manylinux_images", Optional[Dict[str, str]]),
-])
+class BuildOptions(NamedTuple):
+    package_dir: str
+    output_dir: str
+    test_command: Optional[str]
+    test_requires: List[str]
+    test_extras: str
+    before_build: Optional[str]
+    build_verbosity: int
+    build_selector: BuildSelector
+    repair_command: str
+    environment: ParsedEnvironment
+    before_test: str
+    dependency_constraints: Optional[DependencyConstraints]
+    manylinux_images: Optional[Dict[str, str]]
 
-"""
-Replace this definition with a class-style NamedTuple in the
-PEP526 style when Python 3.5 host support is dropped
-"""
 
 resources_dir = os.path.abspath(os.path.join(os.path.dirname(__file__), 'resources'))
 get_pip_script = os.path.join(resources_dir, 'get-pip.py')
diff --git a/cibuildwheel/windows.py b/cibuildwheel/windows.py
index ffa8152a..4e99094b 100644
--- a/cibuildwheel/windows.py
+++ b/cibuildwheel/windows.py
@@ -34,7 +34,11 @@ def get_nuget_args(version: str, arch: str) -> List[str]:
     return [python_name, '-Version', version, '-OutputDirectory', 'C:\\cibw\\python']
 
 
-PythonConfiguration = NamedTuple('PythonConfiguration', [('version', str), ('arch', str), ('identifier', str), ('url', Optional[str])])
+class PythonConfiguration(NamedTuple):
+    version: str
+    arch: str
+    identifier: str
+    url: Optional[str]
 
 
 def get_python_configurations(build_selector: Callable[[str], bool]) -> List[PythonConfiguration]: