diff --git a/src/Formatter/XsdTypeFormatter.php b/src/Formatter/XsdTypeFormatter.php
index 9870cd2..a077ec2 100644
--- a/src/Formatter/XsdTypeFormatter.php
+++ b/src/Formatter/XsdTypeFormatter.php
@@ -4,6 +4,7 @@
 namespace Soap\WsdlReader\Formatter;
 
 use Soap\Engine\Metadata\Model\XsdType;
+use Soap\WsdlReader\Metadata\Predicate\IsConsideredNullableType;
 
 final class XsdTypeFormatter
 {
@@ -11,7 +12,7 @@ public function __invoke(XsdType $xsdType): string
     {
         $meta = $xsdType->getMeta();
         $isList = $meta->isList()->unwrapOr(false) && !$meta->isAlias()->unwrapOr(false);
-        $isNullable = $meta->isNullable()->unwrapOr(false);
+        $isNullable = (new IsConsideredNullableType())($meta);
         $min = $meta->minOccurs()->unwrapOr(1);
         $max = $meta->maxOccurs()->unwrapOr(1);
 
diff --git a/src/Metadata/Predicate/IsConsideredNullableType.php b/src/Metadata/Predicate/IsConsideredNullableType.php
new file mode 100644
index 0000000..250c03e
--- /dev/null
+++ b/src/Metadata/Predicate/IsConsideredNullableType.php
@@ -0,0 +1,29 @@
+<?php
+declare(strict_types=1);
+
+namespace Soap\WsdlReader\Metadata\Predicate;
+
+use Soap\Engine\Metadata\Model\TypeMeta;
+
+final class IsConsideredNullableType
+{
+    public function __invoke(TypeMeta $meta): bool
+    {
+        if ($meta->isNullable()->unwrapOr(false)) {
+            return true;
+        }
+
+        if ($meta->isNil()->unwrapOr(false)) {
+            return true;
+        }
+
+        if ($meta->isAttribute()->unwrapOr(false)) {
+            // If no 'use' is defined, XSD attributes get an implicit default "optional" value
+            if ($meta->use()->unwrapOr('optional') === 'optional') {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}
diff --git a/src/Metadata/Predicate/IsConsideredScalarType.php b/src/Metadata/Predicate/IsConsideredScalarType.php
new file mode 100644
index 0000000..91d237d
--- /dev/null
+++ b/src/Metadata/Predicate/IsConsideredScalarType.php
@@ -0,0 +1,15 @@
+<?php
+declare(strict_types=1);
+
+namespace Soap\WsdlReader\Metadata\Predicate;
+
+use Soap\Engine\Metadata\Model\TypeMeta;
+
+final class IsConsideredScalarType
+{
+    public function __invoke(TypeMeta $meta): bool
+    {
+        return $meta->isSimple()->unwrapOr(false)
+            || $meta->isAttribute()->unwrapOr(false);
+    }
+}
diff --git a/tests/Unit/Metadata/Predicate/IsConsideredNullableTypeTest.php b/tests/Unit/Metadata/Predicate/IsConsideredNullableTypeTest.php
new file mode 100644
index 0000000..0f04141
--- /dev/null
+++ b/tests/Unit/Metadata/Predicate/IsConsideredNullableTypeTest.php
@@ -0,0 +1,60 @@
+<?php
+declare(strict_types=1);
+
+namespace Soap\WsdlReader\Test\Unit\Metadata\Predicate;
+
+use PHPUnit\Framework\TestCase;
+use Soap\Engine\Metadata\Model\TypeMeta;
+use Soap\WsdlReader\Metadata\Predicate\IsConsideredNullableType;
+
+final class IsConsideredNullableTypeTest extends TestCase
+{
+    /**
+     * @dataProvider provideTests
+     *
+     */
+    public function test_it_knows_if_a_type_is_considered_nullable(TypeMeta $meta, bool $expected): void
+    {
+        static::assertSame($expected, (new IsConsideredNullableType())($meta));
+    }
+
+    public static function provideTests()
+    {
+        yield 'empty' => [
+            (new TypeMeta()),
+            false,
+        ];
+        yield 'nullable' => [
+            (new TypeMeta())->withIsNullable(true),
+            true,
+        ];
+        yield 'not-nullable' => [
+            (new TypeMeta())->withIsNullable(false),
+            false,
+        ];
+        yield 'nillable' => [
+            (new TypeMeta())->withIsNil(true),
+            true,
+        ];
+        yield 'not-nillable' => [
+            (new TypeMeta())->withIsNil(false),
+            false,
+        ];
+        yield 'default-attribute' => [
+            (new TypeMeta())->withIsAttribute(true),
+            true,
+        ];
+        yield 'optional-attribute' => [
+            (new TypeMeta())->withIsAttribute(true)->withUse('optional'),
+            true,
+        ];
+        yield 'required-attribute' => [
+            (new TypeMeta())->withIsAttribute(true)->withUse('required'),
+            false,
+        ];
+        yield 'prohibit-attribute' => [
+            (new TypeMeta())->withIsAttribute(true)->withUse('prohibit'),
+            false,
+        ];
+    }
+}
diff --git a/tests/Unit/Metadata/Predicate/IsConsideredScalarTypeTest.php b/tests/Unit/Metadata/Predicate/IsConsideredScalarTypeTest.php
new file mode 100644
index 0000000..e08bac5
--- /dev/null
+++ b/tests/Unit/Metadata/Predicate/IsConsideredScalarTypeTest.php
@@ -0,0 +1,36 @@
+<?php
+declare(strict_types=1);
+
+namespace Soap\WsdlReader\Test\Unit\Metadata\Predicate;
+
+use PHPUnit\Framework\TestCase;
+use Soap\Engine\Metadata\Model\TypeMeta;
+use Soap\WsdlReader\Metadata\Predicate\IsConsideredScalarType;
+
+final class IsConsideredScalarTypeTest extends TestCase
+{
+    /**
+     * @dataProvider provideTests
+     *
+     */
+    public function test_it_knows_if_a_type_is_considered_scalar(TypeMeta $meta, bool $expected): void
+    {
+        static::assertSame($expected, (new IsConsideredScalarType())($meta));
+    }
+
+    public static function provideTests()
+    {
+        yield 'not' => [
+            (new TypeMeta()),
+            false,
+        ];
+        yield 'simple' => [
+            (new TypeMeta())->withIsSimple(true),
+            true,
+        ];
+        yield 'attribute' => [
+            (new TypeMeta())->withIsSimple(true),
+            true,
+        ];
+    }
+}