diff --git a/src/Encoder/Fault/Soap11FaultEncoder.php b/src/Encoder/Fault/Soap11FaultEncoder.php
new file mode 100644
index 0000000..e10ccd7
--- /dev/null
+++ b/src/Encoder/Fault/Soap11FaultEncoder.php
@@ -0,0 +1,50 @@
+<?php
+declare(strict_types=1);
+
+namespace Soap\Encoding\Encoder\Fault;
+
+use RuntimeException;
+use Soap\Encoding\Encoder\Context;
+use Soap\Encoding\Encoder\XmlEncoder;
+use Soap\Encoding\Model\Soap11Fault;
+use VeeWee\Reflecta\Iso\Iso;
+
+/**
+ * @implements XmlEncoder<Soap11Fault, string>
+ */
+final class Soap11FaultEncoder implements XmlEncoder
+{
+    /**
+     * @return Iso<Soap11Fault, string>
+     */
+    public function iso(Context $context): Iso
+    {
+        return new Iso(
+            static fn (Soap11Fault $fault): string => throw new RuntimeException('not implemented yet'),
+            static fn (string $fault): Soap11Fault => throw new RuntimeException('not implemented yet')
+        );
+    }
+}
+
+
+/*
+ *
+ * <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
+    <s:Body>
+        <s:Fault>
+            <faultcode xmlns:a="urn:microsoft-dynamics-schemas/error">
+                a:Microsoft.Dynamics.Nav.Service.WebServices.ServiceBrokerException
+            </faultcode>
+            <faultstring xml:lang="nl-BE">Parameter languagecode in method CategoryList in service DumpServices is
+                null!
+            </faultstring>
+            <detail>
+                <string xmlns="http://schemas.microsoft.com/2003/10/Serialization/">Parameter languagecode in method
+                    CategoryList in service DumpServices is null!
+                </string>
+            </detail>
+        </s:Fault>
+    </s:Body>
+</s:Envelope>
+
+ */
diff --git a/src/Encoder/Fault/Soap12FaultEncoder.php b/src/Encoder/Fault/Soap12FaultEncoder.php
new file mode 100644
index 0000000..cb63b1e
--- /dev/null
+++ b/src/Encoder/Fault/Soap12FaultEncoder.php
@@ -0,0 +1,139 @@
+<?php
+declare(strict_types=1);
+
+namespace Soap\Encoding\Encoder\Fault;
+
+use Soap\Encoding\Encoder\Context;
+use Soap\Encoding\Encoder\XmlEncoder;
+use Soap\Encoding\Model\Soap12Fault;
+use VeeWee\Reflecta\Iso\Iso;
+use VeeWee\Xml\Dom\Document;
+use VeeWee\Xml\Writer\Writer;
+use function VeeWee\Xml\Dom\Xpath\Configurator\namespaces;
+use function VeeWee\Xml\Writer\Builder\children;
+use function VeeWee\Xml\Writer\Builder\namespaced_element;
+use function VeeWee\Xml\Writer\Builder\prefixed_element;
+use function VeeWee\Xml\Writer\Builder\raw;
+use function VeeWee\Xml\Writer\Builder\value;
+use function VeeWee\Xml\Writer\Mapper\memory_output;
+
+/**
+ * @implements XmlEncoder<Soap12Fault, non-empty-string>
+ */
+final class Soap12FaultEncoder implements XmlEncoder
+{
+    private const ENV_NAMESPACE = 'http://www.w3.org/2003/05/soap-envelope';
+
+    /**
+     * @return Iso<Soap12Fault, non-empty-string>
+     */
+    public function iso(Context $context): Iso
+    {
+        return new Iso(
+            $this->to(...),
+            $this->from(...)
+        );
+    }
+
+    private function to(Soap12Fault $fault): string
+    {
+        return Writer::inMemory()
+            ->write(children([
+                namespaced_element(
+                    self::ENV_NAMESPACE,
+                    'env',
+                    'Fault',
+                    children([
+                        prefixed_element(
+                            'env',
+                            'Code',
+                            children([
+                                prefixed_element(
+                                    'env',
+                                    'Value',
+                                    value($fault->code)
+                                ),
+                                ...(
+                                    $fault->subCode
+                                    ? [
+                                        prefixed_element(
+                                            'env',
+                                            'Subcode',
+                                            children([
+                                                prefixed_element(
+                                                    'env',
+                                                    'Value',
+                                                    value($fault->subCode)
+                                                )
+                                            ])
+                                        )
+                                    ]
+                                    : []
+                                ),
+
+                            ])
+                        ),
+                        prefixed_element(
+                            'env',
+                            'Reason',
+                            children([
+                                prefixed_element(
+                                    'env',
+                                    'Text',
+                                    value($fault->reason)
+                                )
+                            ])
+                        ),
+                        ...(
+                            $fault->node
+                                ? [
+                                    prefixed_element(
+                                        'env',
+                                        'Node',
+                                        value($fault->node)
+                                    )
+                                ]
+                                : []
+                        ),
+                        ...(
+                            $fault->role
+                                ? [
+                                    prefixed_element(
+                                        'env',
+                                        'Role',
+                                        value($fault->role)
+                                    )
+                                ]
+                                : []
+                        ),
+                        ...($fault->detail ? [raw($fault->detail)] : []),
+                    ])
+                )
+            ]))
+            ->map(memory_output());
+    }
+
+    /**
+     * @param non-empty-string $fault
+     */
+    private function from(string $fault): Soap12Fault
+    {
+        $document = Document::fromXmlString($fault);
+        $documentElement = $document->locateDocumentElement();
+        $xpath = $document->xpath(namespaces(['env' => $documentElement->namespaceURI]));
+
+        $subCode = $xpath->query('//env:Code/env:Subcode/env:Value');
+        $node = $xpath->query('//env:Node');
+        $role = $xpath->query('//env:Role');
+        $detail = $xpath->query('//env:Detail');
+
+        return new Soap12Fault(
+            code: $xpath->querySingle('//env:Code/env:Value')->textContent,
+            reason: $xpath->querySingle('//env:Reason/env:Text')->textContent,
+            subCode: $subCode->count() ? $subCode->first()->textContent : null,
+            node: $node->count() ? $node->first()->textContent : null,
+            role: $role->count() ? $role->first()->textContent : null,
+            detail: $detail->count() ? Document::fromXmlNode($detail->first())->stringifyDocumentElement() : null,
+        );
+    }
+}
diff --git a/src/Exception/SoapFaultException.php b/src/Exception/SoapFaultException.php
new file mode 100644
index 0000000..7b38afa
--- /dev/null
+++ b/src/Exception/SoapFaultException.php
@@ -0,0 +1,28 @@
+<?php
+declare(strict_types=1);
+
+namespace Soap\Encoding\Exception;
+
+use Psl\Str;
+use RuntimeException;
+use Soap\Encoding\Model\SoapFault;
+
+final class SoapFaultException extends RuntimeException implements ExceptionInterface
+{
+    public function __construct(
+        private readonly SoapFault $fault
+    ) {
+        parent::__construct(
+            Str\format(
+                'A SOAP Fault got triggered: %s (Code: %s)',
+                $this->fault->reason(),
+                $this->fault->code(),
+            ),
+        );
+    }
+
+    public function fault(): SoapFault
+    {
+        return $this->fault;
+    }
+}
diff --git a/src/Model/Soap11Fault.php b/src/Model/Soap11Fault.php
new file mode 100644
index 0000000..c546ab8
--- /dev/null
+++ b/src/Model/Soap11Fault.php
@@ -0,0 +1,11 @@
+<?php
+declare(strict_types=1);
+
+namespace Soap\Encoding\Model;
+
+/**
+ * @see https://www.w3.org/TR/2000/NOTE-SOAP-20000508/#_Toc478383507
+ */
+final class Soap11Fault implements SoapFault
+{
+}
diff --git a/src/Model/Soap12Fault.php b/src/Model/Soap12Fault.php
new file mode 100644
index 0000000..0a0165c
--- /dev/null
+++ b/src/Model/Soap12Fault.php
@@ -0,0 +1,41 @@
+<?php
+declare(strict_types=1);
+
+namespace Soap\Encoding\Model;
+
+/**
+ * https://www.w3.org/TR/soap12-part1/#soapfault
+ *
+ * A mandatory Code element information item (see 5.4.1 SOAP Code Element).
+ * A mandatory Reason element information item (see 5.4.2 SOAP Reason Element).
+ * An optional Node element information item (see 5.4.3 SOAP Node Element).
+ * An optional Role element information item (see 5.4.4 SOAP Role Element).
+ * An optional Detail element information item (see 5.4.5 SOAP Detail Element).
+ */
+final class Soap12Fault implements SoapFault
+{
+    public function __construct(
+        public readonly string $code,
+        public readonly string $reason,
+        public readonly ?string $subCode = null,
+        public readonly ?string $node = null,
+        public readonly ?string $role = null,
+        public readonly ?string $detail = null
+    ) {
+    }
+
+    public function code(): string
+    {
+        return $this->code;
+    }
+
+    public function reason(): string
+    {
+        return $this->reason;
+    }
+
+    public function detail(): ?string
+    {
+        return $this->detail;
+    }
+}
diff --git a/src/Model/SoapFault.php b/src/Model/SoapFault.php
new file mode 100644
index 0000000..53c2e4e
--- /dev/null
+++ b/src/Model/SoapFault.php
@@ -0,0 +1,13 @@
+<?php
+declare(strict_types=1);
+
+namespace Soap\Encoding\Model;
+
+interface SoapFault
+{
+    public function code(): string;
+
+    public function reason(): string;
+
+    public function detail(): ?string;
+}
diff --git a/tests/Unit/Encoder/Fault/Soap12FaultEncoderTest.php b/tests/Unit/Encoder/Fault/Soap12FaultEncoderTest.php
new file mode 100644
index 0000000..ffe1ca8
--- /dev/null
+++ b/tests/Unit/Encoder/Fault/Soap12FaultEncoderTest.php
@@ -0,0 +1,116 @@
+<?php
+declare(strict_types=1);
+
+namespace Soap\Encoding\Test\Unit\Encoder\Fault;
+
+use PHPUnit\Framework\Attributes\CoversClass;
+use Soap\Encoding\Encoder\Fault\Soap12FaultEncoder;
+use Soap\Encoding\Model\Soap12Fault;
+use Soap\Encoding\Test\Unit\Encoder\AbstractEncoderTests;
+use Soap\Engine\Metadata\Model\XsdType;
+use VeeWee\Xml\Dom\Document;
+use function VeeWee\Xml\Dom\Configurator\loader;
+use function VeeWee\Xml\Dom\Configurator\trim_spaces;
+use function VeeWee\Xml\Dom\Loader\xml_string_loader;
+
+#[CoversClass(Soap12FaultEncoder::class)]
+final class Soap12FaultEncoderTest extends AbstractEncoderTests
+{
+    public static function provideIsomorphicCases(): iterable
+    {
+        $baseConfig = [
+            'encoder' => $encoder = new Soap12FaultEncoder(),
+            'context' => $context = self::createContext(
+                // Context is not important.
+                XsdType::guess('Fault')
+            ),
+        ];
+
+        yield 'required-fields-only' => [
+            ...$baseConfig,
+            'xml' => Document::configure(
+                trim_spaces(),
+                loader(xml_string_loader(
+                    <<<EOXML
+                    <env:Fault xmlns:env="http://www.w3.org/2003/05/soap-envelope">
+                        <env:Code>
+                            <env:Value>env:Sender</env:Value>
+                        </env:Code>
+                        <env:Reason>
+                            <env:Text>Sender Timeout</env:Text>
+                        </env:Reason>
+                    </env:Fault>
+                    EOXML
+                ))
+            )->stringifyDocumentElement(),
+            'data' => new Soap12Fault(
+                code: 'env:Sender',
+                reason: 'Sender Timeout',
+            ),
+        ];
+        yield 'subcode-and-details-example' => [
+            ...$baseConfig,
+            'xml' => Document::configure(
+                trim_spaces(),
+                loader(xml_string_loader(
+                    <<<EOXML
+                    <env:Fault xmlns:env="http://www.w3.org/2003/05/soap-envelope">
+                        <env:Code>
+                            <env:Value>env:Sender</env:Value>
+                            <env:Subcode>
+                                <env:Value>m:MessageTimeout</env:Value>
+                            </env:Subcode>
+                        </env:Code>
+                        <env:Reason>
+                            <env:Text>Sender Timeout</env:Text>
+                        </env:Reason>
+                        <env:Detail xmlns:m="http://www.example.org/timeouts" xmlns:env="http://www.w3.org/2003/05/soap-envelope"><m:MaxTime>P5M</m:MaxTime></env:Detail>
+                    </env:Fault>
+                    EOXML
+                ))
+            )->stringifyDocumentElement(),
+            'data' => new Soap12Fault(
+                code: 'env:Sender',
+                subCode: 'm:MessageTimeout',
+                reason: 'Sender Timeout',
+                detail: trim(<<<EOXML
+                <env:Detail xmlns:m="http://www.example.org/timeouts" xmlns:env="http://www.w3.org/2003/05/soap-envelope"><m:MaxTime>P5M</m:MaxTime></env:Detail>
+                EOXML)
+            ),
+        ];
+        yield 'full-example' => [
+            ...$baseConfig,
+            'xml' => Document::configure(
+                trim_spaces(),
+                loader(xml_string_loader(
+                    <<<EOXML
+                    <env:Fault xmlns:env="http://www.w3.org/2003/05/soap-envelope">
+                        <env:Code>
+                            <env:Value>env:Sender</env:Value>
+                            <env:Subcode>
+                                <env:Value>m:MessageTimeout</env:Value>
+                            </env:Subcode>
+                        </env:Code>
+                        <env:Reason>
+                            <env:Text>Sender Timeout</env:Text>
+                        </env:Reason>
+                        <env:Node>urn:node</env:Node>
+                        <env:Role>urn:role</env:Role>
+                        <env:Detail xmlns:m="http://www.example.org/timeouts" xmlns:env="http://www.w3.org/2003/05/soap-envelope"><m:MaxTime>P5M</m:MaxTime></env:Detail>
+                    </env:Fault>
+                    EOXML
+                ))
+            )->stringifyDocumentElement(),
+            'data' => new Soap12Fault(
+                code: 'env:Sender',
+                subCode: 'm:MessageTimeout',
+                reason: 'Sender Timeout',
+                node: 'urn:node',
+                role: 'urn:role',
+                detail: trim(<<<EOXML
+                <env:Detail xmlns:m="http://www.example.org/timeouts" xmlns:env="http://www.w3.org/2003/05/soap-envelope"><m:MaxTime>P5M</m:MaxTime></env:Detail>
+                EOXML)
+            ),
+        ];
+    }
+}