diff --git a/config/install/monitoring.sensor_config.monitoring_git_dirty_tree.yml b/config/install/monitoring.sensor_config.monitoring_git_dirty_tree.yml
index e24c5d1..058b628 100644
--- a/config/install/monitoring.sensor_config.monitoring_git_dirty_tree.yml
+++ b/config/install/monitoring.sensor_config.monitoring_git_dirty_tree.yml
@@ -13,3 +13,4 @@ settings:
   branches_cmd: 'git rev-parse --symbolic --branches'
   actual_branch_cmd: 'git symbolic-ref HEAD --short'
   expected_branch: NULL
+  submodules_cmd: 'git submodule status --recursive'
diff --git a/config/schema/monitoring.schema.yml b/config/schema/monitoring.schema.yml
index f63ad85..21fd1b3 100644
--- a/config/schema/monitoring.schema.yml
+++ b/config/schema/monitoring.schema.yml
@@ -154,6 +154,9 @@ monitoring.settings.monitoring_git_dirty_tree:
     expected_branch:
       type: string
       label: 'Git branch'
+    submodules_cmd:
+      type: string
+      label: 'Check submodules command'
 
 monitoring.settings.monitoring_disappeared_sensors:
   type: monitoring.settings_base
diff --git a/src/Plugin/monitoring/SensorPlugin/GitDirtyTreeSensorPlugin.php b/src/Plugin/monitoring/SensorPlugin/GitDirtyTreeSensorPlugin.php
index 928b0fb..4f38fe9 100644
--- a/src/Plugin/monitoring/SensorPlugin/GitDirtyTreeSensorPlugin.php
+++ b/src/Plugin/monitoring/SensorPlugin/GitDirtyTreeSensorPlugin.php
@@ -39,6 +39,7 @@ class GitDirtyTreeSensorPlugin extends SensorPluginBase implements ExtendedInfoS
   protected $distance;
   protected $branches;
   protected $actualBranch;
+  protected $submodules;
 
   /**
    * {@inheritdoc}
@@ -61,15 +62,28 @@ class GitDirtyTreeSensorPlugin extends SensorPluginBase implements ExtendedInfoS
     }
     $this->status = $this->runSensorCommand($result, 'status_cmd');
     $this->distance = $this->runSensorCommand($result, 'ahead_cmd');
+    $this->submodules = $this->runSensorCommand($result, 'submodules_cmd');
+
+    $wrong_submodules = [];
+    foreach ($this->submodules as $submodule) {
+      $prefix = substr($submodule, 0, 1);
+      if ($prefix == '-' || $prefix == '+') {
+        array_push($wrong_submodules, $submodule);
+      }
+    }
 
     $result->setExpectedValue(0);
     $is_expected_branch = $this->actualBranch === $this->sensorConfig->getSetting('expected_branch');
-    if ($this->status || $this->distance || (!$is_expected_branch && $branch_control)) {
+    if ($this->status || $this->distance || (!$is_expected_branch && $branch_control) || $wrong_submodules) {
       $result->setValue(count($this->status));
+
+      // Critical situations.
       if ($this->status) {
         $result->addStatusMessage('Files in unexpected state: @files', array('@files' => $this->getShortFileList($this->status, 2)));
         $result->setStatus(SensorResultInterface::STATUS_CRITICAL);
       }
+
+      // Warnings.
       if ($this->distance) {
         $result->addStatusMessage('Branch is @distance ahead of origin', array('@distance' => count($this->distance)));
         if ($result->getStatus() != SensorResultInterface::STATUS_CRITICAL) {
@@ -85,6 +99,12 @@ class GitDirtyTreeSensorPlugin extends SensorPluginBase implements ExtendedInfoS
           $result->setStatus(SensorResultInterface::STATUS_WARNING);
         }
       }
+      if ($wrong_submodules) {
+        $result->addStatusMessage('Submodules in unexpected state: @submodules', array('@submodules' => $this->getShortFileList($wrong_submodules, 2)));
+        if ($result->getStatus() != SensorResultInterface::STATUS_CRITICAL) {
+          $result->setStatus(SensorResultInterface::STATUS_WARNING);
+        }
+      }
     }
     else {
       $result->setValue(0);
@@ -170,8 +190,8 @@ class GitDirtyTreeSensorPlugin extends SensorPluginBase implements ExtendedInfoS
     );
     $output['status'] = array(
       '#type' => 'fieldset',
-      '#attributes' => array(),
       '#title' => t('Status'),
+      '#attributes' => array(),
     );
     $output['status']['cmd'] = array(
       '#type' => 'item',
@@ -185,6 +205,23 @@ class GitDirtyTreeSensorPlugin extends SensorPluginBase implements ExtendedInfoS
       '#description' => t('Shows uncommitted, changed and deleted files.'),
       '#description_display' => 'after',
     );
+    $output['submodules'] = array(
+      '#type' => 'fieldset',
+      '#title' => t('Submodules'),
+      '#attributes' => array(),
+    );
+    $output['submodules']['cmd'] = array(
+      '#type' => 'item',
+      '#title' => t('Command'),
+      '#markup' => $this->buildCommand('submodules_cmd'),
+    );
+    $output['submodules']['output'] = array(
+      '#type' => 'item',
+      '#title' => t('Output'),
+      '#markup' => '<pre>' . implode("\n", $this->submodules) . '</pre>',
+      '#description' => t('List all submodules and with a "-" prefix those not initialized and with "+" those in unexpected state.'),
+      '#description_display' => 'after',
+    );
 
     return $output;
   }
diff --git a/src/Tests/MonitoringCoreKernelTest.php b/src/Tests/MonitoringCoreKernelTest.php
index b602a70..af36d7e 100644
--- a/src/Tests/MonitoringCoreKernelTest.php
+++ b/src/Tests/MonitoringCoreKernelTest.php
@@ -436,6 +436,7 @@ class MonitoringCoreKernelTest extends MonitoringUnitTestBase {
     // http://unix.stackexchange.com/questions/48106/what-does-it-mean-to-have-a-dollarsign-prefixed-string-in-a-script.
     $sensor_config->settings['status_cmd'] = 'printf "A addedfile.txt\nM sites/all/modules/monitoring/test/tests/monitoring.core.test\nD deleted file.txt"';
     $sensor_config->settings['ahead_cmd'] = 'true';
+    $sensor_config->settings['submodules_cmd'] = 'true';
     $sensor_config->save();
 
     $result = $this->runSensor('monitoring_git_dirty_tree');
@@ -493,6 +494,36 @@ class MonitoringCoreKernelTest extends MonitoringUnitTestBase {
     $result = $this->runSensor('monitoring_git_dirty_tree');
     $this->assertTrue($result->isOk());
     $this->assertEqual($result->getMessage(), 'Value 0, Git repository clean');
+
+    // Test submodule not initialized.
+    $sensor_config->settings['submodules_cmd'] = 'printf -- "-a5066d1778b9ec7c86631234ff2795e777bdff12 test\n156fff6ee58497fa22b57c32e22e3f13377b4120 test (8.x-1.0-240-g156fff6)"';
+    $sensor_config->save();
+
+    $result = $this->runSensor('monitoring_git_dirty_tree');
+    $this->assertTrue($result->isWarning());
+    $verbose_output = $result->getVerboseOutput();
+    $this->setRawContent(\Drupal::service('renderer')->renderPlain($verbose_output));
+    $this->assertText('-a5066d1778b9ec7c86631234ff2795e777bdff12 test');
+    $this->assertEqual($result->getMessage(), 'Value 0, Submodules in unexpected state: -a5066d1778b9ec7c86631234ff2795e777bdff12 test');
+
+    // Test submodule with uncommited changes.
+    $sensor_config->settings['submodules_cmd'] = 'printf "a5066d1778b9ec7c86631234ff2795e777bdff12 test\n+156fff6ee58497fa22b57c32e22e3f13377b4120 test (8.x-1.0-240-g156fff6)"';
+    $sensor_config->save();
+
+    $result = $this->runSensor('monitoring_git_dirty_tree');
+    $this->assertTrue($result->isWarning());
+    $verbose_output = $result->getVerboseOutput();
+    $this->setRawContent(\Drupal::service('renderer')->renderPlain($verbose_output));
+    $this->assertText('+156fff6ee58497fa22b57c32e22e3f13377b4120 test (8.x-1.0-240-g156fff6)');
+    $this->assertEqual($result->getMessage(), 'Value 0, Submodules in unexpected state: +156fff6ee58497fa22b57c32e22e3f13377b4120 test (8.x-1.0-240-g156fff6)');
+
+    // Test submodules in expected state.
+    $sensor_config->settings['submodules_cmd'] = 'printf "a5066d1778b9ec7c86631234ff2795e777bdff12 test\n156fff6ee58497fa22b57c32e22e3f13377b4120 test (8.x-1.0-240-g156fff6)"';
+    $sensor_config->save();
+
+    $result = $this->runSensor('monitoring_git_dirty_tree');
+    $this->assertTrue($result->isOk());
+    $this->assertEqual($result->getMessage(), 'Value 0, Git repository clean');
   }
 
   /**