diff --git a/src/Xml/Configurator/FlattenXsdImports.php b/src/Xml/Configurator/FlattenXsdImports.php
index af52a5d..ee371d0 100644
--- a/src/Xml/Configurator/FlattenXsdImports.php
+++ b/src/Xml/Configurator/FlattenXsdImports.php
@@ -18,11 +18,13 @@
 use VeeWee\Xml\Exception\RuntimeException;
 use function Psl\Type\instance_of;
 use function Psl\Type\nullable;
+use function Psl\Vec\reverse;
 use function VeeWee\Xml\Dom\Assert\assert_element;
 use function VeeWee\Xml\Dom\Locator\Node\children;
 use function VeeWee\Xml\Dom\Manipulator\Element\copy_named_xmlns_attributes;
 use function VeeWee\Xml\Dom\Manipulator\Node\append_external_node;
 use function VeeWee\Xml\Dom\Manipulator\Node\remove;
+use function VeeWee\Xml\Dom\Xpath\Configurator\functions;
 
 /**
  * This class deals with xsd:import, xsd:include and xsd:redefine tags.
@@ -65,6 +67,8 @@ public function __invoke(DOMDocument $document): DOMDocument
             }
         }
 
+        $this->rearrangeImportsAsFirstElements($xml);
+
         return $document;
     }
 
@@ -219,4 +223,31 @@ private function fixRemovedDefaultXmlnsDeclarationsDuringImport(DOMElement $targ
 
         $target->setAttribute('xmlns', $source->getAttribute('xmlns'));
     }
+
+    /**
+     * Makes sure to rearrange the import statements on top of the flattened XSD schema.
+     * This makes the flattened XSD spec compliant:
+     *
+     * @see https://www.w3.org/TR/xmlschema11-1/#declare-schema
+     *
+     * <schema>
+     * Content: ((include | import | redefine | override | annotation)*,
+     *   (defaultOpenContent, annotation*)?,
+     *   ((simpleType | complexType | group | attributeGroup | element | attribute | notation), annotation*)*)
+     * </schema>
+     *
+     * @throws RuntimeException
+     */
+    private function rearrangeImportsAsFirstElements(Document $xml): void
+    {
+        $xpath = $xml->xpath(new WsdlPreset($xml), functions(['array_reverse']));
+        $imports = $xpath
+            ->query('//schema:import')
+            ->expectAllOfType(DOMElement::class);
+
+        foreach (reverse($imports) as $import) {
+            $parentSchema = assert_element($import->parentNode);
+            $parentSchema->prepend($import);
+        }
+    }
 }
diff --git a/tests/Unit/Xml/Configurator/FlattenXsdImportsTest.php b/tests/Unit/Xml/Configurator/FlattenXsdImportsTest.php
index bbbec67..fe06559 100644
--- a/tests/Unit/Xml/Configurator/FlattenXsdImportsTest.php
+++ b/tests/Unit/Xml/Configurator/FlattenXsdImportsTest.php
@@ -71,5 +71,10 @@ public function provideTestCases()
             'expected' => Document::fromXmlFile(FIXTURE_DIR.'/flattening/result/root-xmlns-import-issue-result.wsdl'),
             canonicalize(),
         ];
+        yield 'rearranged-imports' => [
+            'wsdl' => FIXTURE_DIR.'/flattening/rearranged-imports.wsdl',
+            'expected' => Document::fromXmlFile(FIXTURE_DIR.'/flattening/result/rearranged-imports.wsdl'),
+            comparable(),
+        ];
     }
 }
diff --git a/tests/fixtures/flattening/rearranged-imports.wsdl b/tests/fixtures/flattening/rearranged-imports.wsdl
new file mode 100644
index 0000000..fea0739
--- /dev/null
+++ b/tests/fixtures/flattening/rearranged-imports.wsdl
@@ -0,0 +1,15 @@
+<?xml version="1.0"?>
+<definitions name="InteropTest"
+    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
+    xmlns="http://schemas.xmlsoap.org/wsdl/"
+    targetNamespace="http://soapinterop.org/">
+    <types>
+        <schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://soapinterop.org/xsd">
+            <import namespace="http://soapinterop.org/rearranged-import" schemaLocation="xsd/rearranged-import.xsd" />
+            <xsd:include schemaLocation="xsd/rearranged-include1.xsd" />
+            <xsd:include schemaLocation="xsd/rearranged-include2.xsd" />
+
+            <element name="element1" type="xsd:string" />
+        </schema>
+    </types>
+</definitions>
diff --git a/tests/fixtures/flattening/result/rearranged-imports.wsdl b/tests/fixtures/flattening/result/rearranged-imports.wsdl
new file mode 100644
index 0000000..f2d83bc
--- /dev/null
+++ b/tests/fixtures/flattening/result/rearranged-imports.wsdl
@@ -0,0 +1,20 @@
+<?xml version="1.0"?>
+<definitions name="InteropTest"
+    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
+    xmlns="http://schemas.xmlsoap.org/wsdl/"
+    targetNamespace="http://soapinterop.org/">
+    <types>
+        <schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://soapinterop.org/xsd">
+            <import namespace="http://soapinterop.org/rearranged-import" />
+            <import namespace="http://soapinterop.org/rearranged-import1" />
+            <import namespace="http://soapinterop.org/rearranged-import2" />
+
+            <element name="element1" type="xsd:string" />
+            <element name="includedElement1" type="xsd:string" />
+            <element name="includedElement2" type="xsd:string" />
+        </schema>
+        <schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://soapinterop.org/rearranged-import"></schema>
+        <schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://soapinterop.org/rearranged-import1"></schema>
+        <schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://soapinterop.org/rearranged-import2"></schema>
+    </types>
+</definitions>
diff --git a/tests/fixtures/flattening/xsd/rearranged-import.xsd b/tests/fixtures/flattening/xsd/rearranged-import.xsd
new file mode 100644
index 0000000..2c9b07c
--- /dev/null
+++ b/tests/fixtures/flattening/xsd/rearranged-import.xsd
@@ -0,0 +1 @@
+<schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://soapinterop.org/rearranged-import"></schema>
diff --git a/tests/fixtures/flattening/xsd/rearranged-import1.xsd b/tests/fixtures/flattening/xsd/rearranged-import1.xsd
new file mode 100644
index 0000000..a2559dd
--- /dev/null
+++ b/tests/fixtures/flattening/xsd/rearranged-import1.xsd
@@ -0,0 +1 @@
+<schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://soapinterop.org/rearranged-import1"></schema>
diff --git a/tests/fixtures/flattening/xsd/rearranged-import2.xsd b/tests/fixtures/flattening/xsd/rearranged-import2.xsd
new file mode 100644
index 0000000..eb609d0
--- /dev/null
+++ b/tests/fixtures/flattening/xsd/rearranged-import2.xsd
@@ -0,0 +1 @@
+<schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://soapinterop.org/rearranged-import2"></schema>
diff --git a/tests/fixtures/flattening/xsd/rearranged-include1.xsd b/tests/fixtures/flattening/xsd/rearranged-include1.xsd
new file mode 100644
index 0000000..acfbdd6
--- /dev/null
+++ b/tests/fixtures/flattening/xsd/rearranged-include1.xsd
@@ -0,0 +1,6 @@
+<schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="http://soapinterop.org/xsd">
+
+    <import namespace="http://soapinterop.org/rearranged-import1" schemaLocation="rearranged-import1.xsd" />
+
+    <element name="includedElement1" type="xsd:string" />
+</schema>
diff --git a/tests/fixtures/flattening/xsd/rearranged-include2.xsd b/tests/fixtures/flattening/xsd/rearranged-include2.xsd
new file mode 100644
index 0000000..4f61863
--- /dev/null
+++ b/tests/fixtures/flattening/xsd/rearranged-include2.xsd
@@ -0,0 +1,6 @@
+<schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="http://soapinterop.org/xsd">
+
+    <import namespace="http://soapinterop.org/rearranged-import2" schemaLocation="rearranged-import2.xsd" />
+
+    <element name="includedElement2" type="xsd:string" />
+</schema>