diff --git a/civicrm.php b/civicrm.php
index b96edad..244d04c 100644
--- a/civicrm.php
+++ b/civicrm.php
@@ -87,6 +87,21 @@
   define( 'CIVICRM_PLUGIN_DIR', plugin_dir_path(CIVICRM_PLUGIN_FILE) );
 }
 
+if ( !defined( 'CIVICRM_WP_PHP_MINIMUM' ) ) {
+  /**
+   * Minimum required PHP
+   *
+   * Note: This duplicates CRM_Upgrade_Form::MINIMUM_PHP_VERSION. The
+   * duplication helps avoid dependency issues. (Reading `Form::MINIMUM_PHP_VERSION`
+   * requires loading `civicrm.settings.php`, but that triggers a parse-error
+   * on PHP 5.x.)
+   *
+   * @see CRM_Upgrade_Form::MINIMUM_PHP_VERSION
+   * @see CiviWP\PhpVersionTest::testConstantMatch()
+   */
+  define( 'CIVICRM_WP_PHP_MINIMUM', '7.0.0' );
+}
+
 /*
  * The constant CIVICRM_SETTINGS_PATH is also defined in civicrm.config.php and
  * may already have been defined there - e.g. by cron or external scripts.
@@ -817,6 +832,19 @@ public function query_vars( $query_vars ) {
   // CiviCRM Initialisation
   // ---------------------------------------------------------------------------
 
+  protected function assertPhpSupport() {
+    // Need to check this before bootstrapping - once we start bootstrapping, the error messages will become ugly.
+    if ( version_compare( PHP_VERSION, CIVICRM_WP_PHP_MINIMUM ) < 0 ) {
+      echo '<p>' .
+         sprintf(
+          __( 'CiviCRM requires PHP version %s or greater. You are running PHP version %s', 'civicrm' ),
+          CIVICRM_WP_PHP_MINIMUM,
+          PHP_VERSION
+         ) .
+         '<p>';
+      exit();
+    }
+  }
 
   /**
    * Initialize CiviCRM.
@@ -836,18 +864,7 @@ public function initialize() {
 
     if ( ! $initialized ) {
 
-      // Check for php version and ensure its greater than minPhpVersion
-      $minPhpVersion = '5.3.4';
-      if ( version_compare( PHP_VERSION, $minPhpVersion ) < 0 ) {
-        echo '<p>' .
-           sprintf(
-            __( 'CiviCRM requires PHP Version %s or greater. You are running PHP Version %s', 'civicrm' ),
-            $minPhpVersion,
-            PHP_VERSION
-           ) .
-           '<p>';
-        exit();
-      }
+      $this->assertPhpSupport();
 
       // Check for settings
       if ( ! CIVICRM_INSTALLED ) {
@@ -1059,6 +1076,7 @@ public function add_menu_items() {
    * @since 4.4
    */
   public function run_installer() {
+    $this->assertPhpSupport();
     $civicrmCore = CIVICRM_PLUGIN_DIR . 'civicrm';
 
     $setupPaths = array(
diff --git a/tests/phpunit/CiviWP/PhpVersionTest.php b/tests/phpunit/CiviWP/PhpVersionTest.php
new file mode 100644
index 0000000..42eab3e
--- /dev/null
+++ b/tests/phpunit/CiviWP/PhpVersionTest.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace CiviWP;
+
+use Civi\Test\EndToEndInterface;
+
+class PhpVersionTest extends \PHPUnit_Framework_TestCase implements EndToEndInterface {
+
+  /**
+   * CIVICRM_WP_PHP_MINIMUM (civicrm.module) should match MINIMUM_PHP_VERSION (CRM/Upgrade/Form.php).
+   *
+   * The literal value should be duplicated in the define() to prevent dependency issues.
+   */
+  public function testConstantMatch() {
+    $constantFile = $this->getModulePath() . '/civicrm.php';
+    $this->assertFileExists($constantFile);
+    $content = file_get_contents($constantFile);
+    if (preg_match(";define\\(\\s*'CIVICRM_WP_PHP_MINIMUM'\\s*,\\s*'(.*)'\\s*\\);", $content, $m)) {
+      $this->assertEquals(\CRM_Upgrade_Form::MINIMUM_PHP_VERSION, $m[1]);
+    }
+    else {
+      $this->fail('Failed to find CIVICRM_WP_PHP_MINIMUM in ' . $constantFile);
+    }
+  }
+
+  /**
+   * @return string
+   *   Ex: '/var/www/wp-content/plugins/civicrm'
+   */
+  protected function getModulePath() {
+    return dirname(dirname(dirname(__DIR__)));
+  }
+
+}