diff --git a/CHANGELOG.md b/CHANGELOG.md
index be448a2..d588368 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,7 +10,8 @@ All notable changes to this project will be documented in this file, in reverse
 
 ### Changed
 
-- Nothing.
+- [#25](https://github.com/zendframework/zend-escaper/pull/25) changes the behavior of the `Escaper` constructor; it now raises an
+  exception for non-null, non-string `$encoding` arguments.
 
 ### Deprecated
 
diff --git a/src/Escaper.php b/src/Escaper.php
index 49b3264..5cec968 100644
--- a/src/Escaper.php
+++ b/src/Escaper.php
@@ -95,7 +95,11 @@ class Escaper
     public function __construct($encoding = null)
     {
         if ($encoding !== null) {
-            $encoding = (string) $encoding;
+            if (! is_string($encoding)) {
+                throw new Exception\InvalidArgumentException(
+                    get_class($this) . ' constructor parameter must be a string, received ' . gettype($encoding)
+                );
+            }
             if ($encoding === '') {
                 throw new Exception\InvalidArgumentException(
                     get_class($this) . ' constructor parameter does not allow a blank value'
diff --git a/test/EscaperTest.php b/test/EscaperTest.php
index d0520d7..f71f58e 100644
--- a/test/EscaperTest.php
+++ b/test/EscaperTest.php
@@ -180,6 +180,15 @@ public function setUp()
         $this->escaper = new Escaper('UTF-8');
     }
 
+    /**
+     * @expectedException \Zend\Escaper\Exception\InvalidArgumentException
+     * @expectedExceptionMessage Zend\Escaper\Escaper constructor parameter must be a string, received integer
+     */
+    public function testSettingEncodingToNonStringShouldThrowException()
+    {
+        $escaper = new Escaper(1);
+    }
+
     /**
      * @expectedException \Zend\Escaper\Exception\InvalidArgumentException
      */