diff --git a/src/pip/_internal/req/constructors.py b/src/pip/_internal/req/constructors.py
index 8f7dc507c7d..37dbd32e7b8 100644
--- a/src/pip/_internal/req/constructors.py
+++ b/src/pip/_internal/req/constructors.py
@@ -209,7 +209,7 @@ def install_req_from_editable(
     constraint: bool = False,
     user_supplied: bool = False,
     permit_editable_wheels: bool = False,
-    config_settings: Optional[Dict[str, str]] = None,
+    config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
 ) -> InstallRequirement:
 
     parts = parse_req_from_editable(editable_req)
@@ -385,7 +385,7 @@ def install_req_from_line(
     constraint: bool = False,
     line_source: Optional[str] = None,
     user_supplied: bool = False,
-    config_settings: Optional[Dict[str, str]] = None,
+    config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
 ) -> InstallRequirement:
     """Creates an InstallRequirement from a name, which might be a
     requirement, directory containing 'setup.py', filename, or URL.
@@ -417,7 +417,7 @@ def install_req_from_req_string(
     isolated: bool = False,
     use_pep517: Optional[bool] = None,
     user_supplied: bool = False,
-    config_settings: Optional[Dict[str, str]] = None,
+    config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
 ) -> InstallRequirement:
     try:
         req = get_requirement(req_string)
diff --git a/src/pip/_internal/req/req_install.py b/src/pip/_internal/req/req_install.py
index fa5620e1d6e..9c5457510e4 100644
--- a/src/pip/_internal/req/req_install.py
+++ b/src/pip/_internal/req/req_install.py
@@ -86,7 +86,7 @@ def __init__(
         *,
         global_options: Optional[List[str]] = None,
         hash_options: Optional[Dict[str, List[str]]] = None,
-        config_settings: Optional[Dict[str, str]] = None,
+        config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
         constraint: bool = False,
         extras: Collection[str] = (),
         user_supplied: bool = False,
diff --git a/src/pip/_internal/utils/misc.py b/src/pip/_internal/utils/misc.py
index baa1ba7eac2..81101b859d0 100644
--- a/src/pip/_internal/utils/misc.py
+++ b/src/pip/_internal/utils/misc.py
@@ -32,6 +32,7 @@
     Tuple,
     Type,
     TypeVar,
+    Union,
     cast,
 )
 
@@ -669,7 +670,7 @@ def __init__(
     def build_wheel(
         self,
         wheel_directory: str,
-        config_settings: Optional[Dict[str, str]] = None,
+        config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
         metadata_directory: Optional[str] = None,
     ) -> str:
         cs = self.config_holder.config_settings
@@ -678,7 +679,9 @@ def build_wheel(
         )
 
     def build_sdist(
-        self, sdist_directory: str, config_settings: Optional[Dict[str, str]] = None
+        self,
+        sdist_directory: str,
+        config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
     ) -> str:
         cs = self.config_holder.config_settings
         return super().build_sdist(sdist_directory, config_settings=cs)
@@ -686,7 +689,7 @@ def build_sdist(
     def build_editable(
         self,
         wheel_directory: str,
-        config_settings: Optional[Dict[str, str]] = None,
+        config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
         metadata_directory: Optional[str] = None,
     ) -> str:
         cs = self.config_holder.config_settings
@@ -695,19 +698,19 @@ def build_editable(
         )
 
     def get_requires_for_build_wheel(
-        self, config_settings: Optional[Dict[str, str]] = None
+        self, config_settings: Optional[Dict[str, Union[str, List[str]]]] = None
     ) -> List[str]:
         cs = self.config_holder.config_settings
         return super().get_requires_for_build_wheel(config_settings=cs)
 
     def get_requires_for_build_sdist(
-        self, config_settings: Optional[Dict[str, str]] = None
+        self, config_settings: Optional[Dict[str, Union[str, List[str]]]] = None
     ) -> List[str]:
         cs = self.config_holder.config_settings
         return super().get_requires_for_build_sdist(config_settings=cs)
 
     def get_requires_for_build_editable(
-        self, config_settings: Optional[Dict[str, str]] = None
+        self, config_settings: Optional[Dict[str, Union[str, List[str]]]] = None
     ) -> List[str]:
         cs = self.config_holder.config_settings
         return super().get_requires_for_build_editable(config_settings=cs)
@@ -715,7 +718,7 @@ def get_requires_for_build_editable(
     def prepare_metadata_for_build_wheel(
         self,
         metadata_directory: str,
-        config_settings: Optional[Dict[str, str]] = None,
+        config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
         _allow_fallback: bool = True,
     ) -> str:
         cs = self.config_holder.config_settings
@@ -728,7 +731,7 @@ def prepare_metadata_for_build_wheel(
     def prepare_metadata_for_build_editable(
         self,
         metadata_directory: str,
-        config_settings: Optional[Dict[str, str]] = None,
+        config_settings: Optional[Dict[str, Union[str, List[str]]]] = None,
         _allow_fallback: bool = True,
     ) -> str:
         cs = self.config_holder.config_settings