diff --git a/src/Header/ContentType.php b/src/Header/ContentType.php
index 45852c05..eb520d5b 100644
--- a/src/Header/ContentType.php
+++ b/src/Header/ContentType.php
@@ -10,14 +10,22 @@
 namespace Zend\Mail\Header;
 
 use Zend\Mail\Headers;
+use Zend\Mime\Mime;
 
-class ContentType implements HeaderInterface
+class ContentType implements UnstructuredInterface
 {
     /**
      * @var string
      */
     protected $type;
 
+    /**
+     * Header encoding
+     *
+     * @var string
+     */
+    protected $encoding = 'ASCII';
+
     /**
      * @var array
      */
@@ -66,6 +74,12 @@ public function getFieldValue($format = HeaderInterface::FORMAT_RAW)
 
         $values = [$prepared];
         foreach ($this->parameters as $attribute => $value) {
+            if (HeaderInterface::FORMAT_ENCODED === $format && !Mime::isPrintable($value)) {
+                $this->encoding = 'UTF-8';
+                $value = HeaderWrap::wrap($value, $this);
+                $this->encoding = 'ASCII';
+            }
+
             $values[] = sprintf('%s="%s"', $attribute, $value);
         }
 
@@ -74,18 +88,18 @@ public function getFieldValue($format = HeaderInterface::FORMAT_RAW)
 
     public function setEncoding($encoding)
     {
-        // This header must be always in US-ASCII
+        $this->encoding = $encoding;
         return $this;
     }
 
     public function getEncoding()
     {
-        return 'ASCII';
+        return $this->encoding;
     }
 
     public function toString()
     {
-        return 'Content-Type: ' . $this->getFieldValue();
+        return 'Content-Type: ' . $this->getFieldValue(HeaderInterface::FORMAT_ENCODED);
     }
 
     /**
@@ -135,8 +149,10 @@ public function addParameter($name, $value)
         if (! HeaderValue::isValid($name)) {
             throw new Exception\InvalidArgumentException('Invalid content-type parameter name detected');
         }
-        if (! HeaderValue::isValid($value)) {
-            throw new Exception\InvalidArgumentException('Invalid content-type parameter value detected');
+        if (! HeaderWrap::canBeEncoded($value)) {
+            throw new Exception\InvalidArgumentException(
+                'Parameter value must be composed of printable US-ASCII or UTF-8 characters.'
+            );
         }
 
         $this->parameters[$name] = $value;
diff --git a/test/Header/ContentTypeTest.php b/test/Header/ContentTypeTest.php
index 2b6230a8..24824557 100644
--- a/test/Header/ContentTypeTest.php
+++ b/test/Header/ContentTypeTest.php
@@ -10,37 +10,21 @@
 namespace ZendTest\Mail\Header;
 
 use Zend\Mail\Header\ContentType;
+use Zend\Mail\Header\Exception\InvalidArgumentException;
+use Zend\Mail\Header\HeaderInterface;
+use Zend\Mail\Header\UnstructuredInterface;
 
 /**
  * @group      Zend_Mail
  */
 class ContentTypeTest extends \PHPUnit_Framework_TestCase
 {
-    public function testContentTypeFromStringCreatesValidContentTypeHeader()
+    public function testImplementsHeaderInterface()
     {
-        $contentTypeHeader = ContentType::fromString('Content-Type: xxx/yyy');
-        $this->assertInstanceOf('Zend\Mail\Header\HeaderInterface', $contentTypeHeader);
-        $this->assertInstanceOf('Zend\Mail\Header\ContentType', $contentTypeHeader);
-    }
-
-    public function testContentTypeGetFieldNameReturnsHeaderName()
-    {
-        $contentTypeHeader = new ContentType();
-        $this->assertEquals('Content-Type', $contentTypeHeader->getFieldName());
-    }
+        $header = new ContentType();
 
-    public function testContentTypeGetFieldValueReturnsProperValue()
-    {
-        $contentTypeHeader = new ContentType();
-        $contentTypeHeader->setType('foo/bar');
-        $this->assertEquals('foo/bar', $contentTypeHeader->getFieldValue());
-    }
-
-    public function testContentTypeToStringReturnsHeaderFormattedString()
-    {
-        $contentTypeHeader = new ContentType();
-        $contentTypeHeader->setType('foo/bar');
-        $this->assertEquals("Content-Type: foo/bar", $contentTypeHeader->toString());
+        $this->assertInstanceOf(UnstructuredInterface::class, $header);
+        $this->assertInstanceOf(HeaderInterface::class, $header);
     }
 
     /**
@@ -55,26 +39,6 @@ public function testTrailingSemiColonFromString()
         $this->assertEquals(['boundary' => 'Apple-Mail=_1B852F10-F9C6-463D-AADD-CD503A5428DD'], $params);
     }
 
-    public function testProvidingParametersIntroducesHeaderFolding()
-    {
-        $header = new ContentType();
-        $header->setType('application/x-unit-test');
-        $header->addParameter('charset', 'us-ascii');
-        $string = $header->toString();
-
-        $this->assertContains("Content-Type: application/x-unit-test;", $string);
-        $this->assertContains(";\r\n charset=\"us-ascii\"", $string);
-    }
-
-    public function testExtractsExtraInformationFromContentType()
-    {
-        $contentTypeHeader = ContentType::fromString(
-            'Content-Type: multipart/alternative; boundary="Apple-Mail=_1B852F10-F9C6-463D-AADD-CD503A5428DD"'
-        );
-        $params = $contentTypeHeader->getParameters();
-        $this->assertEquals($params, ['boundary' => 'Apple-Mail=_1B852F10-F9C6-463D-AADD-CD503A5428DD']);
-    }
-
     public function testExtractsExtraInformationWithoutBeingConfusedByTrailingSemicolon()
     {
         $header = ContentType::fromString('Content-Type: application/pdf;name="foo.pdf";');
@@ -82,53 +46,46 @@ public function testExtractsExtraInformationWithoutBeingConfusedByTrailingSemico
     }
 
     /**
-     * @group #2728
-     *
-     * Tests setting different MIME types
+     * @dataProvider setTypeProvider
      */
-    public function testSetContentType()
+    public function testFromString($type, $parameters, $fieldValue, $expectedToString)
     {
-        $header = new ContentType();
-
-        $header->setType('application/vnd.ms-excel');
-        $this->assertEquals('Content-Type: application/vnd.ms-excel', $header->toString());
-
-        $header->setType('application/rss+xml');
-        $this->assertEquals('Content-Type: application/rss+xml', $header->toString());
-
-        $header->setType('video/mp4');
-        $this->assertEquals('Content-Type: video/mp4', $header->toString());
-
-        $header->setType('message/rfc822');
-        $this->assertEquals('Content-Type: message/rfc822', $header->toString());
+        $header = ContentType::fromString($expectedToString);
+
+        $this->assertInstanceOf(ContentType::class, $header);
+        $this->assertEquals('Content-Type', $header->getFieldName(), 'getFieldName() value not match');
+        $this->assertEquals($type, $header->getType(), 'getType() value not match');
+        $this->assertEquals($fieldValue, $header->getFieldValue(), 'getFieldValue() value not match');
+        $this->assertEquals($parameters, $header->getParameters(), 'getParameters() value not match');
+        $this->assertEquals($expectedToString, $header->toString(), 'toString() value not match');
     }
 
     /**
-     * @group ZF2015-04
+     * @dataProvider setTypeProvider
      */
-    public function testFromStringRaisesExceptionForInvalidName()
+    public function testSetType($type, $parameters, $fieldValue, $expectedToString)
     {
-        $this->setExpectedException('Zend\Mail\Header\Exception\InvalidArgumentException', 'header name');
-        $header = ContentType::fromString('Content-Type' . chr(32) . ': text/html');
-    }
+        $header = new ContentType();
 
-    public function headerLines()
-    {
-        return [
-            'newline'      => ["Content-Type: text/html;\nlevel=1"],
-            'cr-lf'        => ["Content-Type: text/html\r\n;level=1",],
-            'multiline'    => ["Content-Type: text/html;\r\nlevel=1\r\nq=0.1"],
-        ];
+        $header->setType($type);
+        foreach ($parameters as $name => $value) {
+            $header->addParameter($name, $value);
+        }
+
+        $this->assertEquals('Content-Type', $header->getFieldName(), 'getFieldName() value not match');
+        $this->assertEquals($type, $header->getType(), 'getType() value not match');
+        $this->assertEquals($fieldValue, $header->getFieldValue(), 'getFieldValue() value not match');
+        $this->assertEquals($parameters, $header->getParameters(), 'getParameters() value not match');
+        $this->assertEquals($expectedToString, $header->toString(), 'toString() value not match');
     }
 
     /**
-     * @dataProvider headerLines
-     * @group ZF2015-04
+     * @dataProvider invalidHeaderLinesProvider
      */
-    public function testFromStringRaisesExceptionForNonFoldingMultilineValues($headerLine)
+    public function testFromStringThrowException($headerLine, $expectedException, $exceptionMessage)
     {
-        $this->setExpectedException('Zend\Mail\Header\Exception\InvalidArgumentException', 'header value');
-        $header = ContentType::fromString($headerLine);
+        $this->setExpectedException($expectedException, $exceptionMessage);
+        ContentType::fromString($headerLine);
     }
 
     /**
@@ -142,24 +99,66 @@ public function testFromStringHandlesContinuations()
     }
 
     /**
-     * @group ZF2015-04
+     * @dataProvider invalidParametersProvider
      */
-    public function testAddParameterRaisesInvalidArgumentExceptionForInvalidParameterName()
+    public function testAddParameterThrowException($paramName, $paramValue, $expectedException, $exceptionMessage)
     {
         $header = new ContentType();
         $header->setType('text/html');
-        $this->setExpectedException('Zend\Mail\Header\Exception\InvalidArgumentException', 'parameter name');
-        $header->addParameter("b\r\na\rr\n", "baz");
+
+        $this->setExpectedException($expectedException, $exceptionMessage);
+        $header->addParameter($paramName, $paramValue);
     }
 
-    /**
-     * @group ZF2015-04
-     */
-    public function testAddParameterRaisesInvalidArgumentExceptionForInvalidParameterValue()
+    public function setTypeProvider()
     {
-        $header = new ContentType();
-        $header->setType('text/html');
-        $this->setExpectedException('Zend\Mail\Header\Exception\InvalidArgumentException', 'parameter value');
-        $header->addParameter('foo', "\nbar\r\nbaz\r");
+        $foldingHeaderLine = "Content-Type: foo/baz;\r\n charset=\"us-ascii\"";
+        $foldingFieldValue = "foo/baz;\r\n charset=\"us-ascii\"";
+
+        $encodedHeaderLine = "Content-Type: foo/baz;\r\n name=\"=?UTF-8?Q?=C3=93?=\"";
+        $encodedFieldValue = "foo/baz;\r\n name=\"Ó\"";
+
+        // @codingStandardsIgnoreStart
+        return [
+            // Description => [$type, $parameters, $fieldValue, toString()]
+            // @group #2728
+            'foo/a.b-c' => ['foo/a.b-c', [], 'foo/a.b-c', 'Content-Type: foo/a.b-c'],
+            'foo/a+b'   => ['foo/a+b'  , [], 'foo/a+b'  , 'Content-Type: foo/a+b'],
+            'foo/baz'   => ['foo/baz'  , [], 'foo/baz'  , 'Content-Type: foo/baz'],
+            'parameter use header folding' => ['foo/baz'  , ['charset' => 'us-ascii'], $foldingFieldValue, $foldingHeaderLine],
+            'encoded characters' => ['foo/baz'  , ['name' => 'Ó'], $encodedFieldValue, $encodedHeaderLine],
+        ];
+        // @codingStandardsIgnoreEnd
+    }
+
+    public function invalidParametersProvider()
+    {
+        $invalidArgumentException = InvalidArgumentException::class;
+
+        // @codingStandardsIgnoreStart
+        return [
+            // Description => [param name, param value, expected exception, exception message contain]
+
+            // @group ZF2015-04
+            'invalid name' => ["b\r\na\rr\n", 'baz', $invalidArgumentException, 'parameter name'],
+        ];
+        // @codingStandardsIgnoreEnd
+    }
+
+    public function invalidHeaderLinesProvider()
+    {
+        $invalidArgumentException = InvalidArgumentException::class;
+
+        // @codingStandardsIgnoreStart
+        return [
+            // Description => [header line, expected exception, exception message contain]
+
+            // @group ZF2015-04
+            'invalid name' => ['Content-Type' . chr(32) . ': text/html', $invalidArgumentException, 'header name'],
+            'newline'   => ["Content-Type: text/html;\nlevel=1", $invalidArgumentException, 'header value'],
+            'cr-lf'     => ["Content-Type: text/html\r\n;level=1", $invalidArgumentException, 'header value'],
+            'multiline' => ["Content-Type: text/html;\r\nlevel=1\r\nq=0.1", $invalidArgumentException, 'header value'],
+        ];
+        // @codingStandardsIgnoreEnd
     }
 }