diff --git a/src/applications/maniphest/editor/ManiphestTransactionEditor.php b/src/applications/maniphest/editor/ManiphestTransactionEditor.php
--- a/src/applications/maniphest/editor/ManiphestTransactionEditor.php
+++ b/src/applications/maniphest/editor/ManiphestTransactionEditor.php
@@ -19,6 +19,7 @@
     $types[] = ManiphestTransaction::TYPE_EDGE;
     $types[] = ManiphestTransaction::TYPE_SUBPRIORITY;
     $types[] = ManiphestTransaction::TYPE_PROJECT_COLUMN;
+    $types[] = ManiphestTransaction::TYPE_UNBLOCK;
     $types[] = PhabricatorTransactions::TYPE_VIEW_POLICY;
     $types[] = PhabricatorTransactions::TYPE_EDIT_POLICY;
 
@@ -84,6 +85,7 @@
       case ManiphestTransaction::TYPE_EDGE:
       case ManiphestTransaction::TYPE_SUBPRIORITY:
       case ManiphestTransaction::TYPE_PROJECT_COLUMN:
+      case ManiphestTransaction::TYPE_UNBLOCK:
         return $xaction->getNewValue();
     }
   }
@@ -244,6 +246,63 @@
     }
   }
 
+  protected function applyFinalEffects(
+    PhabricatorLiskDAO $object,
+    array $xactions) {
+
+    // When we change the status of a task, update tasks this tasks blocks
+    // with a message to the effect of "alincoln resolved blocking task Txxx."
+    $unblock_xaction = null;
+    foreach ($xactions as $xaction) {
+      switch ($xaction->getTransactionType()) {
+        case ManiphestTransaction::TYPE_STATUS:
+          $unblock_xaction = $xaction;
+          break;
+      }
+    }
+
+    if ($unblock_xaction !== null) {
+      $blocked_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
+        $object->getPHID(),
+        PhabricatorEdgeConfig::TYPE_TASK_DEPENDED_ON_BY_TASK);
+      if ($blocked_phids) {
+        // In theory we could apply these through policies, but that seems a
+        // little bit surprising. For now, use the actor's vision.
+        $blocked_tasks = id(new ManiphestTaskQuery())
+          ->setViewer($this->getActor())
+          ->withPHIDs($blocked_phids)
+          ->execute();
+
+        $old = $unblock_xaction->getOldValue();
+        $new = $unblock_xaction->getNewValue();
+
+        foreach ($blocked_tasks as $blocked_task) {
+          $xactions = array();
+
+          $xactions[] = id(new ManiphestTransaction())
+            ->setTransactionType(ManiphestTransaction::TYPE_UNBLOCK)
+            ->setOldValue(array($object->getPHID() => $old))
+            ->setNewValue(array($object->getPHID() => $new));
+
+          // TODO: We should avoid notifiying users about these indirect
+          // changes if they are getting a notification about the current
+          // change, so you don't get a pile of extra notifications if you are
+          // subscribed to this task.
+
+          id(new ManiphestTransactionEditor())
+            ->setActor($this->getActor())
+            ->setContentSource($this->getContentSource())
+            ->setContinueOnNoEffect(true)
+            ->setContinueOnMissingFields(true)
+            ->applyTransactions($blocked_task, $xactions);
+        }
+      }
+    }
+
+    return $xactions;
+  }
+
+
   protected function shouldSendMail(
     PhabricatorLiskDAO $object,
     array $xactions) {
diff --git a/src/applications/maniphest/storage/ManiphestTransaction.php b/src/applications/maniphest/storage/ManiphestTransaction.php
--- a/src/applications/maniphest/storage/ManiphestTransaction.php
+++ b/src/applications/maniphest/storage/ManiphestTransaction.php
@@ -14,6 +14,8 @@
   const TYPE_SUBPRIORITY = 'subpriority';
   const TYPE_PROJECT_COLUMN = 'projectcolumn';
 
+  const TYPE_UNBLOCK = 'unblock';
+
   // NOTE: this type is deprecated. Keep it around for legacy installs
   // so any transactions render correctly.
   const TYPE_ATTACH = 'attach';
@@ -34,6 +36,7 @@
     switch ($this->getTransactionType()) {
       case self::TYPE_PROJECT_COLUMN:
       case self::TYPE_EDGE:
+      case self::TYPE_UNBLOCK:
         return false;
     }
 
@@ -87,7 +90,11 @@
             array_keys(idx($old, 'FILE', array())),
           ));
         break;
-
+      case self::TYPE_UNBLOCK:
+        foreach (array_keys($new) as $phid) {
+          $phids[] = $phid;
+        }
+        break;
     }
 
     return $phids;
@@ -233,6 +240,22 @@
       case self::TYPE_EDGE:
       case self::TYPE_ATTACH:
         return pht('Attached');
+
+      case self::TYPE_UNBLOCK:
+        $old_status = head($old);
+        $new_status = head($new);
+
+        $old_closed = ManiphestTaskStatus::isClosedStatus($old_status);
+        $new_closed = ManiphestTaskStatus::isClosedStatus($new_status);
+
+        if ($old_closed && !$new_closed) {
+          return pht('Block');
+        } else if (!$old_closed && $new_closed) {
+          return pht('Unblock');
+        } else {
+          return pht('Blocker');
+        }
+
     }
 
     return parent::getActionName();
@@ -290,6 +313,9 @@
       case self::TYPE_ATTACH:
         return 'fa-thumb-tack';
 
+      case self::TYPE_UNBLOCK:
+        return 'fa-shield';
+
     }
 
     return parent::getIcon();
@@ -352,6 +378,38 @@
             $new_name);
         }
 
+      case self::TYPE_UNBLOCK:
+        $blocker_phid = key($new);
+        $old_status = head($old);
+        $new_status = head($new);
+
+        $old_closed = ManiphestTaskStatus::isClosedStatus($old_status);
+        $new_closed = ManiphestTaskStatus::isClosedStatus($new_status);
+
+        $old_name = ManiphestTaskStatus::getTaskStatusName($old_status);
+        $new_name = ManiphestTaskStatus::getTaskStatusName($new_status);
+
+        if ($old_closed && !$new_closed) {
+          return pht(
+            '%s reopened blocking task %s as "%s".',
+            $this->renderHandleLink($author_phid),
+            $this->renderHandleLink($blocker_phid),
+            $new_name);
+        } else if (!$old_closed && $new_closed) {
+          return pht(
+            '%s closed blocking task %s as "%s".',
+            $this->renderHandleLink($author_phid),
+            $this->renderHandleLink($blocker_phid),
+            $new_name);
+        } else {
+          return pht(
+            '%s changed the status of blocking task %s from "%s" to "%s".',
+            $this->renderHandleLink($author_phid),
+            $this->renderHandleLink($blocker_phid),
+            $old_name,
+            $new_name);
+        }
+
       case self::TYPE_OWNER:
         if ($author_phid == $new) {
           return pht(
@@ -551,6 +609,16 @@
             $new_name);
         }
 
+      case self::TYPE_UNBLOCK:
+
+        // TODO: We should probably not show these in feed; they're highly
+        // redundant. For now, just use the normal titles. Right now, we can't
+        // publish something to noficiations without also publishing it to feed.
+        // Fix that, then stop these from rendering in feed only.
+
+        break;
+
+
       case self::TYPE_OWNER:
         if ($author_phid == $new) {
           return pht(