diff --git a/src/poetry/config/config.py b/src/poetry/config/config.py
index 22906db6a19..0bcc6966e25 100644
--- a/src/poetry/config/config.py
+++ b/src/poetry/config/config.py
@@ -31,7 +31,7 @@ def boolean_validator(val: str) -> bool:
 
 
 def boolean_normalizer(val: str) -> bool:
-    return val in ["true", "1"]
+    return val.lower() in ["true", "1"]
 
 
 def int_normalizer(val: str) -> int:
diff --git a/tests/config/test_config.py b/tests/config/test_config.py
index 8afcd0e6596..28f532cff6a 100644
--- a/tests/config/test_config.py
+++ b/tests/config/test_config.py
@@ -53,7 +53,17 @@ def test_config_get_processes_depended_on_values(
 
 def generate_environment_variable_tests() -> Iterator[tuple[str, str, str, bool]]:
     data: list[tuple[Normalizer, list[tuple[str, Any]]]] = [
-        (boolean_normalizer, [("true", True), ("false", False)]),
+        (
+            boolean_normalizer,
+            [
+                ("true", True),
+                ("false", False),
+                ("True", True),
+                ("False", False),
+                ("1", True),
+                ("0", False),
+            ],
+        ),
         (int_normalizer, [("4", 4), ("2", 2)]),
     ]