diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -2102,6 +2102,7 @@
     'PhabricatorCalendarICSWriter' => 'applications/calendar/util/PhabricatorCalendarICSWriter.php',
     'PhabricatorCalendarIconSet' => 'applications/calendar/icon/PhabricatorCalendarIconSet.php',
     'PhabricatorCalendarImport' => 'applications/calendar/storage/PhabricatorCalendarImport.php',
+    'PhabricatorCalendarImportDisableController' => 'applications/calendar/controller/PhabricatorCalendarImportDisableController.php',
     'PhabricatorCalendarImportDisableTransaction' => 'applications/calendar/xaction/PhabricatorCalendarImportDisableTransaction.php',
     'PhabricatorCalendarImportEditController' => 'applications/calendar/controller/PhabricatorCalendarImportEditController.php',
     'PhabricatorCalendarImportEditEngine' => 'applications/calendar/editor/PhabricatorCalendarImportEditEngine.php',
@@ -6905,6 +6906,7 @@
       'PhabricatorApplicationTransactionInterface',
       'PhabricatorDestructibleInterface',
     ),
+    'PhabricatorCalendarImportDisableController' => 'PhabricatorCalendarController',
     'PhabricatorCalendarImportDisableTransaction' => 'PhabricatorCalendarImportTransactionType',
     'PhabricatorCalendarImportEditController' => 'PhabricatorCalendarController',
     'PhabricatorCalendarImportEditEngine' => 'PhabricatorEditEngine',
diff --git a/src/applications/calendar/controller/PhabricatorCalendarImportDisableController.php b/src/applications/calendar/controller/PhabricatorCalendarImportDisableController.php
new file mode 100644
--- /dev/null
+++ b/src/applications/calendar/controller/PhabricatorCalendarImportDisableController.php
@@ -0,0 +1,71 @@
+<?php
+
+final class PhabricatorCalendarImportDisableController
+  extends PhabricatorCalendarController {
+
+  public function handleRequest(AphrontRequest $request) {
+    $viewer = $request->getViewer();
+
+    $import = id(new PhabricatorCalendarImportQuery())
+      ->setViewer($viewer)
+      ->withIDs(array($request->getURIData('id')))
+      ->requireCapabilities(
+        array(
+          PhabricatorPolicyCapability::CAN_VIEW,
+          PhabricatorPolicyCapability::CAN_EDIT,
+        ))
+      ->executeOne();
+    if (!$import) {
+      return new Aphront404Response();
+    }
+
+    $import_uri = $import->getURI();
+    $is_disable = !$import->getIsDisabled();
+
+    if (!$import->getEngine()->canDisable($viewer, $import)) {
+      $reason = $import->getEngine()->explainCanDisable($viewer, $import);
+      return $this->newDialog()
+        ->setTitle(pht('Unable to Disable'))
+        ->appendParagraph($reason)
+        ->addCancelButton($import_uri);
+    }
+
+    if ($request->isFormPost()) {
+      $xactions = array();
+      $xactions[] = id(new PhabricatorCalendarImportTransaction())
+        ->setTransactionType(
+          PhabricatorCalendarImportDisableTransaction::TRANSACTIONTYPE)
+        ->setNewValue($is_disable ? 1 : 0);
+
+      $editor = id(new PhabricatorCalendarImportEditor())
+        ->setActor($viewer)
+        ->setContinueOnNoEffect(true)
+        ->setContinueOnMissingFields(true)
+        ->setContentSourceFromRequest($request);
+
+      $editor->applyTransactions($import, $xactions);
+
+      return id(new AphrontRedirectResponse())->setURI($import_uri);
+    }
+
+    if ($is_disable) {
+      $title = pht('Disable Import');
+      $body = pht(
+        'Disable this import? Events from this source will no longer be '.
+        'updated.');
+      $button = pht('Disable Import');
+    } else {
+      $title = pht('Enable Import');
+      $body = pht(
+        'Enable this import? Events from this source will be updated again.');
+      $button = pht('Enable Import');
+    }
+
+    return $this->newDialog()
+      ->setTitle($title)
+      ->appendParagraph($body)
+      ->addCancelButton($import_uri)
+      ->addSubmitButton($button);
+  }
+
+}
diff --git a/src/applications/calendar/controller/PhabricatorCalendarImportViewController.php b/src/applications/calendar/controller/PhabricatorCalendarImportViewController.php
--- a/src/applications/calendar/controller/PhabricatorCalendarImportViewController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarImportViewController.php
@@ -80,6 +80,7 @@
     $id = $import->getID();
 
     $curtain = $this->newCurtainView($import);
+    $engine = $import->getEngine();
 
     $can_edit = PhabricatorPolicyFilter::hasCapability(
       $viewer,
@@ -89,6 +90,8 @@
     $edit_uri = "import/edit/{$id}/";
     $edit_uri = $this->getApplicationURI($edit_uri);
 
+    $can_disable = ($can_edit && $engine->canDisable($viewer, $import));
+
     $curtain->addAction(
       id(new PhabricatorActionView())
         ->setName(pht('Edit Import'))
@@ -111,7 +114,7 @@
       id(new PhabricatorActionView())
         ->setName($disable_name)
         ->setIcon($disable_icon)
-        ->setDisabled(!$can_edit)
+        ->setDisabled(!$can_disable)
         ->setWorkflow(true)
         ->setHref($disable_uri));
 
diff --git a/src/applications/calendar/import/PhabricatorCalendarICSImportEngine.php b/src/applications/calendar/import/PhabricatorCalendarICSImportEngine.php
--- a/src/applications/calendar/import/PhabricatorCalendarICSImportEngine.php
+++ b/src/applications/calendar/import/PhabricatorCalendarICSImportEngine.php
@@ -70,5 +70,20 @@
   }
 
 
+  public function canDisable(
+    PhabricatorUser $viewer,
+    PhabricatorCalendarImport $import) {
+    return false;
+  }
+
+  public function explainCanDisable(
+    PhabricatorUser $viewer,
+    PhabricatorCalendarImport $import) {
+    return pht(
+      'You can not disable import of an ICS file because the entire import '.
+      'occurs immediately when you upload the file. There is no further '.
+      'activity to disable.');
+  }
+
 
 }
diff --git a/src/applications/calendar/import/PhabricatorCalendarImportEngine.php b/src/applications/calendar/import/PhabricatorCalendarImportEngine.php
--- a/src/applications/calendar/import/PhabricatorCalendarImportEngine.php
+++ b/src/applications/calendar/import/PhabricatorCalendarImportEngine.php
@@ -21,6 +21,16 @@
     PhabricatorUser $viewer,
     PhabricatorCalendarImport $import);
 
+  abstract public function canDisable(
+    PhabricatorUser $viewer,
+    PhabricatorCalendarImport $import);
+
+  public function explainCanDisable(
+    PhabricatorUser $viewer,
+    PhabricatorCalendarImport $import) {
+    throw new PhutilMethodNotImplementedException();
+  }
+
   final public static function getAllImportEngines() {
     return id(new PhutilClassMapQuery())
       ->setAncestorClass(__CLASS__)