diff --git a/src/ElasticaSpecification/ExpressionBuilder/NotBuilder.php b/src/ElasticaSpecification/ExpressionBuilder/NotBuilder.php
new file mode 100644
index 0000000..9d2cca4
--- /dev/null
+++ b/src/ElasticaSpecification/ExpressionBuilder/NotBuilder.php
@@ -0,0 +1,45 @@
+<?php
+
+namespace GBProd\ElasticaSpecification\ExpressionBuilder;
+
+use Elastica\QueryBuilder;
+use GBProd\ElasticaSpecification\Registry;
+use GBProd\Specification\Not;
+use GBProd\Specification\Specification;
+
+/**
+ * Expression Builder for Not specification
+ *
+ * @author gbprod <contact@gb-prod.fr>
+ */
+class NotBuilder implements Builder
+{
+    /**
+     * @var Registry
+     */
+    private $registry;
+
+    /**
+     * @param Registry $registry
+     */
+    public function __construct(Registry $registry)
+    {
+        $this->registry = $registry;
+    }
+
+    /**
+     * {inheritdoc}
+     */
+    public function build(Specification $spec, QueryBuilder $qb)
+    {
+        if (!$spec instanceof Not) {
+            throw new \InvalidArgumentException();
+        }
+
+        $firstPartBuilder  = $this->registry->getBuilder($spec->getWrappedSpecification());
+
+        return $qb->query()->bool()
+            ->addMustNot($firstPartBuilder->build($spec->getWrappedSpecification(), $qb))
+        ;
+    }
+}
diff --git a/tests/ElasticaSpecification/ExpressionBuilder/NotBuilderTest.php b/tests/ElasticaSpecification/ExpressionBuilder/NotBuilderTest.php
new file mode 100644
index 0000000..c294e0f
--- /dev/null
+++ b/tests/ElasticaSpecification/ExpressionBuilder/NotBuilderTest.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace Tests\GBProd\ElasticaSpecification;
+
+use Elastica\QueryBuilder;
+use Elastica\Query\AbstractQuery;
+use Elastica\Query\BoolQuery;
+use GBProd\ElasticaSpecification\ExpressionBuilder\NotBuilder;
+use GBProd\ElasticaSpecification\ExpressionBuilder\Builder;
+use GBProd\ElasticaSpecification\Registry;
+use GBProd\Specification\Not;
+use GBProd\Specification\Specification;
+
+class NotBuilderTest extends \PHPUnit_Framework_TestCase
+{
+    public function testConstruct()
+    {
+        $builder = new NotBuilder(new Registry());
+
+        $this->assertInstanceOf(NotBuilder::class, $builder);
+    }
+
+    public function testBuildReturnsNotExpression()
+    {
+        $not = $this->createNot();
+        $registry = $this->createRegistry($not);
+
+        $builder = new NotBuilder($registry);
+
+        $query = $builder->build($not, new QueryBuilder());
+
+        $this->assertInstanceOf(BoolQuery::class, $query);
+
+        $this->assertArrayHasKey('bool', $query->toArray());
+        $this->assertArrayHasKey('must_not', $query->toArray()['bool']);
+        $this->assertCount(1, $query->toArray()['bool']['must_not']);
+    }
+
+    /**
+     * @return Not
+     */
+    private function createNot()
+    {
+        return new Not(
+            $this->createMock(Specification::class)
+        );
+    }
+
+    /**
+     * @param Not $not
+     *
+     * @return Registry
+     */
+    private function createRegistry($not)
+    {
+        $builder = $this->createMock(Builder::class);
+        $builder
+            ->expects($this->any())
+            ->method('build')
+            ->willReturn($this->createMock(AbstractQuery::class))
+        ;
+
+        $registry = new Registry();
+
+        $registry->register(get_class($not->getWrappedSpecification()), $builder);
+
+        return $registry;
+    }
+
+
+    public function testBuildThrowExceptionIfNotNotSpecification()
+    {
+        $spec = $this->createMock(Specification::class);
+        $registry = new Registry();
+        $builder = new NotBuilder($registry);
+
+        $this->setExpectedException(\InvalidArgumentException::class);
+
+        $expr = $builder->build($spec, new QueryBuilder());
+    }
+}