diff --git a/akka-http-tests/src/test/scala/akka/http/server/directives/MarshallingDirectivesSpec.scala b/akka-http-tests/src/test/scala/akka/http/server/directives/MarshallingDirectivesSpec.scala
index 00334d0282..96550a70c0 100644
--- a/akka-http-tests/src/test/scala/akka/http/server/directives/MarshallingDirectivesSpec.scala
+++ b/akka-http-tests/src/test/scala/akka/http/server/directives/MarshallingDirectivesSpec.scala
@@ -6,6 +6,7 @@ package akka.http.server
 package directives
 
 import scala.xml.NodeSeq
+import org.scalatest.Inside
 import akka.http.marshallers.xml.ScalaXmlSupport
 import akka.http.unmarshalling._
 import akka.http.marshalling._
@@ -16,14 +17,14 @@ import HttpCharsets._
 import headers._
 import spray.json.DefaultJsonProtocol._
 
-class MarshallingDirectivesSpec extends RoutingSpec {
+class MarshallingDirectivesSpec extends RoutingSpec with Inside {
   import ScalaXmlSupport._
 
   private val iso88592 = HttpCharsets.getForKey("iso-8859-2").get
   implicit val IntUnmarshaller: FromEntityUnmarshaller[Int] =
     nodeSeqUnmarshaller(ContentTypeRange(`text/xml`, iso88592), `text/html`) map {
       case NodeSeq.Empty ⇒ throw Unmarshaller.NoContentException
-      case x             ⇒ x.text.toInt
+      case x             ⇒ { val i = x.text.toInt; require(i >= 0); i }
     }
 
   implicit val IntMarshaller: ToEntityMarshaller[Int] =
@@ -60,6 +61,23 @@ class MarshallingDirectivesSpec extends RoutingSpec {
           entity(as[String]) { _ ⇒ validate(false, "Problem") { completeOk } }
       } ~> check { rejection shouldEqual ValidationRejection("Problem") }
     }
+    "return a ValidationRejection if the request entity is semantically invalid (IllegalArgumentException)" in {
+      Put("/", HttpEntity(ContentType(`text/xml`, iso88592), "<int>-3</int>")) ~> {
+        entity(as[Int]) { _ ⇒ completeOk }
+      } ~> check {
+        inside(rejection) {
+          case ValidationRejection("requirement failed", Some(_: IllegalArgumentException)) ⇒
+        }
+      }
+    }
+    "return a MalformedRequestContentRejection if unmarshalling failed due to a not further classified error" in {
+      Put("/", HttpEntity(`text/xml`, "<foo attr='illegal xml'")) ~> {
+        entity(as[NodeSeq]) { _ ⇒ completeOk }
+      } ~> check {
+        rejection shouldEqual MalformedRequestContentRejection(
+          "XML document structures must start and end within the same entity.", None)
+      }
+    }
     "extract an Option[T] from the requests entity using the in-scope Unmarshaller" in {
       Put("/", <p>cool</p>) ~> {
         entity(as[Option[NodeSeq]]) { echoComplete }
diff --git a/akka-http/src/main/scala/akka/http/server/Rejection.scala b/akka-http/src/main/scala/akka/http/server/Rejection.scala
index 208a721219..636d1854e2 100644
--- a/akka-http/src/main/scala/akka/http/server/Rejection.scala
+++ b/akka-http/src/main/scala/akka/http/server/Rejection.scala
@@ -94,7 +94,10 @@ case class TooManyRangesRejection(maxRanges: Int) extends Rejection
 
 /**
  * Rejection created by unmarshallers.
- * Signals that the request was rejected because there was an error while unmarshalling the request content
+ * Signals that the request was rejected because unmarshalling failed with an error that wasn't
+ * an `IllegalArgumentException`. Usually that means that the request content was not of the expected format.
+ * Note that semantic issues with the request content (e.g. because some parameter was out of range)
+ * will usually trigger a `ValidationRejection` instead.
  */
 case class MalformedRequestContentRejection(message: String, cause: Option[Throwable] = None) extends Rejection
 
@@ -161,7 +164,9 @@ case object AuthorizationFailedRejection extends Rejection
 case class MissingCookieRejection(cookieName: String) extends Rejection
 
 /**
- * Rejection created by the `validation` directive.
+ * Rejection created by the `validation` directive as well as for `IllegalArgumentExceptions`
+ * thrown by domain model constructors (e.g. via `require`).
+ * It signals that an expected value was semantically invalid.
  */
 case class ValidationRejection(message: String, cause: Option[Throwable] = None) extends Rejection
 
diff --git a/akka-http/src/main/scala/akka/http/server/directives/MarshallingDirectives.scala b/akka-http/src/main/scala/akka/http/server/directives/MarshallingDirectives.scala
index 402d45fcfc..9cfbe43f88 100644
--- a/akka-http/src/main/scala/akka/http/server/directives/MarshallingDirectives.scala
+++ b/akka-http/src/main/scala/akka/http/server/directives/MarshallingDirectives.scala
@@ -27,6 +27,7 @@ trait MarshallingDirectives {
         case Success(value) ⇒ provide(value)
         case Failure(Unmarshaller.NoContentException) ⇒ reject(RequestEntityExpectedRejection)
         case Failure(Unmarshaller.UnsupportedContentTypeException(x)) ⇒ reject(UnsupportedRequestContentTypeRejection(x))
+        case Failure(x: IllegalArgumentException) ⇒ reject(ValidationRejection(x.getMessage.nullAsEmpty, Some(x)))
         case Failure(x) ⇒ reject(MalformedRequestContentRejection(x.getMessage.nullAsEmpty, Option(x.getCause)))
       }
     } & cancelRejections(RequestEntityExpectedRejection.getClass, classOf[UnsupportedRequestContentTypeRejection])