diff --git a/src/SemanticComparator.php b/src/SemanticComparator.php
index 02580bd..d9f73d8 100644
--- a/src/SemanticComparator.php
+++ b/src/SemanticComparator.php
@@ -15,27 +15,20 @@
  * @since 1.0.0-rc.1
  * @see http://semver.org
  */
-class SemanticComparator
+class SemanticComparator implements SemanticComparatorInterface
 {
     /**
-     * @param SemanticVersion $left
-     * @param SemanticVersion $right
-     * @return int
-     * @see compare()
+     * @inheritdoc
      */
-    public function __invoke(SemanticVersion $left, SemanticVersion $right)
+    public function __invoke(SemanticVersionInterface $left, SemanticVersionInterface $right)
     {
         return $this->compare($left, $right);
     }
 
     /**
-     * Build metadata is ignored when determining version precedence.
-     *
-     * @param SemanticVersion $left
-     * @param SemanticVersion $right
-     * @return int `0` if both versions are equal, `< 0` if `$left` is smaller and `> 0` if `$left` is greater.
+     * @inheritdoc
      */
-    public function compare(SemanticVersion $left, SemanticVersion $right)
+    public function compare(SemanticVersionInterface $left, SemanticVersionInterface $right)
     {
         $result = $this->compareMajorMinorPatch($left, $right);
 
@@ -47,11 +40,11 @@ public function compare(SemanticVersion $left, SemanticVersion $right)
     }
 
     /**
-     * @param SemanticVersion $left
-     * @param SemanticVersion $right
+     * @param SemanticVersionInterface $left
+     * @param SemanticVersionInterface $right
      * @return int
      */
-    private function compareMajorMinorPatch(SemanticVersion $left, SemanticVersion $right)
+    private function compareMajorMinorPatch(SemanticVersionInterface $left, SemanticVersionInterface $right)
     {
         $result = $left->getMajor() - $right->getMajor();
 
@@ -67,11 +60,11 @@ private function compareMajorMinorPatch(SemanticVersion $left, SemanticVersion $
     }
 
     /**
-     * @param SemanticVersion $left
-     * @param SemanticVersion $right
+     * @param SemanticVersionInterface $left
+     * @param SemanticVersionInterface $right
      * @return int
      */
-    private function comparePre(SemanticVersion $left, SemanticVersion $right)
+    private function comparePre(SemanticVersionInterface $left, SemanticVersionInterface $right)
     {
         if ($left->getPre() === '') {
             return $right->getPre() === '' ? 0 : 1;
diff --git a/src/SemanticComparatorInterface.php b/src/SemanticComparatorInterface.php
new file mode 100644
index 0000000..645f18b
--- /dev/null
+++ b/src/SemanticComparatorInterface.php
@@ -0,0 +1,36 @@
+<?php
+
+/**
+ * (c) Dennis Meckel
+ *
+ * For the full copyright and license information,
+ * please view the LICENSE file that was distributed with this source code.
+ */
+
+namespace Rayne\SemanticVersioning;
+
+/**
+ * Semantic Versioning Comparator.
+ *
+ * @since 1.0.0-rc.3
+ * @see http://semver.org
+ */
+interface SemanticComparatorInterface
+{
+    /**
+     * @param SemanticVersionInterface $left
+     * @param SemanticVersionInterface $right
+     * @return int
+     * @see compare()
+     */
+    public function __invoke(SemanticVersionInterface $left, SemanticVersionInterface $right);
+
+    /**
+     * Build metadata is ignored when determining version precedence.
+     *
+     * @param SemanticVersionInterface $left
+     * @param SemanticVersionInterface $right
+     * @return int `0` if both versions are equal, `< 0` if `$left` is smaller and `> 0` if `$left` is greater.
+     */
+    public function compare(SemanticVersionInterface $left, SemanticVersionInterface $right);
+}
diff --git a/src/SemanticVersion.php b/src/SemanticVersion.php
index ae3aca1..825d13a 100644
--- a/src/SemanticVersion.php
+++ b/src/SemanticVersion.php
@@ -16,7 +16,7 @@
  * @since 1.0.0-rc.1
  * @see http://semver.org
  */
-class SemanticVersion
+class SemanticVersion implements SemanticVersionInterface
 {
     /**
      * @var int
@@ -81,7 +81,7 @@ public function __construct($version)
     }
 
     /**
-     * @return string
+     * @inheritdoc
      */
     public function __toString()
     {
@@ -129,7 +129,7 @@ private function buildException()
     }
 
     /**
-     * @return int Non-negative integer without leading zeroes.
+     * @inheritdoc
      */
     public function getMajor()
     {
@@ -137,7 +137,7 @@ public function getMajor()
     }
 
     /**
-     * @return int Non-negative integer without leading zeroes.
+     * @inheritdoc
      */
     public function getMinor()
     {
@@ -145,7 +145,7 @@ public function getMinor()
     }
 
     /**
-     * @return int Non-negative integer without leading zeroes.
+     * @inheritdoc
      */
     public function getPatch()
     {
@@ -153,7 +153,7 @@ public function getPatch()
     }
 
     /**
-     * @return string Optional pre-release information.
+     * @inheritdoc
      */
     public function getPre()
     {
@@ -161,8 +161,7 @@ public function getPre()
     }
 
     /**
-     * @return string[]
-     * @since 1.0.0-rc.2
+     * @inheritdoc
      */
     public function getPreStack()
     {
@@ -170,7 +169,7 @@ public function getPreStack()
     }
 
     /**
-     * @return string Optional metadata.
+     * @inheritdoc
      */
     public function getMeta()
     {
@@ -178,8 +177,7 @@ public function getMeta()
     }
 
     /**
-     * @return string[]
-     * @since 1.0.0-rc.2
+     * @inheritdoc
      */
     public function getMetaStack()
     {
@@ -187,7 +185,7 @@ public function getMetaStack()
     }
 
     /**
-     * @return string
+     * @inheritdoc
      */
     public function getVersion()
     {
diff --git a/src/SemanticVersionInterface.php b/src/SemanticVersionInterface.php
new file mode 100644
index 0000000..29258b9
--- /dev/null
+++ b/src/SemanticVersionInterface.php
@@ -0,0 +1,68 @@
+<?php
+
+/**
+ * (c) Dennis Meckel.
+ *
+ * For the full copyright and license information,
+ * please view the LICENSE file that was distributed with this source code.
+ */
+
+namespace Rayne\SemanticVersioning;
+
+/**
+ * Interprets the semantic versioning format `MAJOR.MINOR.PATCH-PRE+META`.
+ *
+ * @since 1.0.0-rc.3
+ * @see http://semver.org
+ */
+interface SemanticVersionInterface
+{
+    /**
+     * @return string
+     */
+    public function __toString();
+
+    /**
+     * @return int Non-negative integer without leading zeroes.
+     */
+    public function getMajor();
+
+    /**
+     * @return int Non-negative integer without leading zeroes.
+     */
+    public function getMinor();
+
+    /**
+     * @return int Non-negative integer without leading zeroes.
+     */
+    public function getPatch();
+
+    /**
+     * @return string Optional pre-release information.
+     */
+    public function getPre();
+
+    /**
+     * @return string[]
+     *
+     * @since 1.0.0-rc.2
+     */
+    public function getPreStack();
+
+    /**
+     * @return string Optional metadata.
+     */
+    public function getMeta();
+
+    /**
+     * @return string[]
+     *
+     * @since 1.0.0-rc.2
+     */
+    public function getMetaStack();
+
+    /**
+     * @return string
+     */
+    public function getVersion();
+}
diff --git a/src/autoload.php b/src/autoload.php
index 8eafb8d..f82d39e 100644
--- a/src/autoload.php
+++ b/src/autoload.php
@@ -10,5 +10,7 @@
  */
 
 require_once __DIR__ . '/NoSemanticVersionException.php';
+require_once __DIR__ . '/SemanticComparatorInterface.php';
 require_once __DIR__ . '/SemanticComparator.php';
+require_once __DIR__ . '/SemanticVersionInterface.php';
 require_once __DIR__ . '/SemanticVersion.php';
diff --git a/tests/SemanticComparatorTest.php b/tests/SemanticComparatorTest.php
index e6ee7bc..e54ea6e 100644
--- a/tests/SemanticComparatorTest.php
+++ b/tests/SemanticComparatorTest.php
@@ -86,10 +86,10 @@ public function provideEqualVersions()
 
     /**
      * @dataProvider provideEqualVersions
-     * @param SemanticVersion $left
-     * @param SemanticVersion $right
+     * @param SemanticVersionInterface $left
+     * @param SemanticVersionInterface $right
      */
-    public function testEqualComparison(SemanticVersion $left, SemanticVersion $right)
+    public function testEqualComparison(SemanticVersionInterface $left, SemanticVersionInterface $right)
     {
         $comparator = new SemanticComparator();
 
@@ -102,10 +102,10 @@ public function testEqualComparison(SemanticVersion $left, SemanticVersion $righ
 
     /**
      * @dataProvider provideSmallerGreaterVersions
-     * @param SemanticVersion $smaller
-     * @param SemanticVersion $greater
+     * @param SemanticVersionInterface $smaller
+     * @param SemanticVersionInterface $greater
      */
-    public function testNotEqualComparison(SemanticVersion $smaller, SemanticVersion $greater)
+    public function testNotEqualComparison(SemanticVersionInterface $smaller, SemanticVersionInterface $greater)
     {
         $comparator = new SemanticComparator();