diff --git a/src/Forms/UrlField.php b/src/Forms/UrlField.php
index 4d5493fc6..4904b79df 100644
--- a/src/Forms/UrlField.php
+++ b/src/Forms/UrlField.php
@@ -53,12 +53,12 @@ class UrlField extends TextField
     }
 
     /**
-     * Set which protocols valid URLs are allowed to have
+     * Set which protocols valid URLs are allowed to have.
+     * Passing an empty array will result in using configured defaults.
      */
     public function setAllowedProtocols(array $protocols): static
     {
-        // Ensure the array isn't associative so we can use 0 index in validate().
-        $this->protocols = array_keys($protocols);
+        $this->protocols = $protocols;
         return $this;
     }
 
@@ -67,10 +67,12 @@ class UrlField extends TextField
      */
     public function getAllowedProtocols(): array
     {
-        if (empty($this->protocols)) {
-            return static::config()->get('default_protocols');
+        $protocols = $this->protocols;
+        if (empty($protocols)) {
+            $protocols = static::config()->get('default_protocols');
         }
-        return $this->protocols;
+        // Ensure the array isn't associative so we can use 0 index in validate().
+        return array_values($protocols);
     }
 
     /**
diff --git a/tests/php/Forms/UrlFieldTest.php b/tests/php/Forms/UrlFieldTest.php
index 077a85e79..07f9fbfd3 100644
--- a/tests/php/Forms/UrlFieldTest.php
+++ b/tests/php/Forms/UrlFieldTest.php
@@ -89,4 +89,23 @@ class UrlFieldTest extends SapphireTest
         $expectedCount = $valid ? 0 : 1;
         $this->assertEquals($expectedCount, count($validator->getErrors()));
     }
+
+    public function testAllowedProtocols(): void
+    {
+        $field = new UrlField('MyUrl');
+        // Defaults should be http and https
+        $this->assertSame(['https', 'http'], $field->getAllowedProtocols());
+
+        // Defaults change with config, and ignore keys
+        UrlField::config()->set('default_protocols', ['my-key' => 'ftp']);
+        $this->assertSame(['ftp'], $field->getAllowedProtocols());
+
+        // Can set explicit protocols - again keys are ignored
+        $field->setAllowedProtocols(['http', 'key' => 'irc', 'nntp']);
+        $this->assertSame(['http', 'irc', 'nntp'], $field->getAllowedProtocols());
+
+        // Can reset back to config defaults
+        $field->setAllowedProtocols([]);
+        $this->assertSame(['ftp'], $field->getAllowedProtocols());
+    }
 }