diff --git a/src/wp-includes/compat.php b/src/wp-includes/compat.php
index 69f01fadfd..e32b6efe97 100644
--- a/src/wp-includes/compat.php
+++ b/src/wp-includes/compat.php
@@ -449,16 +449,6 @@ if ( ! function_exists( 'sodium_crypto_box' ) ) {
 	require ABSPATH . WPINC . '/sodium_compat/autoload.php';
 }
 
-/**
- * Polyfill for the SPL autoloader. In PHP 5.2 (but not 5.3 and later), SPL can
- * be disabled, and PHP 7.2 raises notices if the compiler finds an __autoload()
- * function declaration. Function availability is checked here, and the
- * autoloader is included only if necessary.
- */
-if ( ! function_exists( 'spl_autoload_register' ) ) {
-	require_once ABSPATH . WPINC . '/spl-autoload-compat.php';
-}
-
 if ( ! function_exists( 'is_countable' ) ) {
 	/**
 	 * Polyfill for is_countable() function added in PHP 7.3.
diff --git a/src/wp-includes/spl-autoload-compat.php b/src/wp-includes/spl-autoload-compat.php
index 599b6046b3..982d9c2a83 100644
--- a/src/wp-includes/spl-autoload-compat.php
+++ b/src/wp-includes/spl-autoload-compat.php
@@ -5,96 +5,10 @@
  *
  * See https://core.trac.wordpress.org/ticket/41134
  *
+ * @deprecated 5.3.0 No longer needed as the minimum PHP requirement has moved beyond PHP 5.3.
+ *
  * @package PHP
  * @access private
  */
 
-if ( ! function_exists( 'spl_autoload_register' ) ) {
-	$_wp_spl_autoloaders = array();
-
-	/**
-	 * Autoloader compatibility callback.
-	 *
-	 * @since 4.6.0
-	 *
-	 * @param string $classname Class to attempt autoloading.
-	 */
-	function __autoload( $classname ) {
-		global $_wp_spl_autoloaders;
-		foreach ( $_wp_spl_autoloaders as $autoloader ) {
-			if ( ! is_callable( $autoloader ) ) {
-				// Avoid the extra warning if the autoloader isn't callable.
-				continue;
-			}
-
-			call_user_func( $autoloader, $classname );
-
-			// If it has been autoloaded, stop processing.
-			if ( class_exists( $classname, false ) ) {
-				return;
-			}
-		}
-	}
-
-	/**
-	 * Registers a function to be autoloaded.
-	 *
-	 * @since 4.6.0
-	 *
-	 * @param callable $autoload_function The function to register.
-	 * @param bool     $throw             Optional. Whether the function should throw an exception
-	 *                                    if the function isn't callable. Default true.
-	 * @param bool     $prepend           Whether the function should be prepended to the stack.
-	 *                                    Default false.
-	 */
-	function spl_autoload_register( $autoload_function, $throw = true, $prepend = false ) {
-		if ( $throw && ! is_callable( $autoload_function ) ) {
-			// String not translated to match PHP core.
-			throw new Exception( 'Function not callable' );
-		}
-
-		global $_wp_spl_autoloaders;
-
-		// Don't allow multiple registration.
-		if ( in_array( $autoload_function, $_wp_spl_autoloaders ) ) {
-			return;
-		}
-
-		if ( $prepend ) {
-			array_unshift( $_wp_spl_autoloaders, $autoload_function );
-		} else {
-			$_wp_spl_autoloaders[] = $autoload_function;
-		}
-	}
-
-	/**
-	 * Unregisters an autoloader function.
-	 *
-	 * @since 4.6.0
-	 *
-	 * @param callable $function The function to unregister.
-	 * @return bool True if the function was unregistered, false if it could not be.
-	 */
-	function spl_autoload_unregister( $function ) {
-		global $_wp_spl_autoloaders;
-		foreach ( $_wp_spl_autoloaders as &$autoloader ) {
-			if ( $autoloader === $function ) {
-				unset( $autoloader );
-				return true;
-			}
-		}
-
-		return false;
-	}
-
-	/**
-	 * Retrieves the registered autoloader functions.
-	 *
-	 * @since 4.6.0
-	 *
-	 * @return array List of autoloader functions.
-	 */
-	function spl_autoload_functions() {
-		return $GLOBALS['_wp_spl_autoloaders'];
-	}
-}
+_deprecated_file( basename( __FILE__ ), '5.3.0', null, 'SPL can no longer be disabled as of PHP 5.3.' );