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
@@ -554,6 +554,7 @@
     'DifferentialRevisionStatus' => 'applications/differential/constants/DifferentialRevisionStatus.php',
     'DifferentialRevisionSummaryHeraldField' => 'applications/differential/herald/DifferentialRevisionSummaryHeraldField.php',
     'DifferentialRevisionSummaryTransaction' => 'applications/differential/xaction/DifferentialRevisionSummaryTransaction.php',
+    'DifferentialRevisionTestPlanTransaction' => 'applications/differential/xaction/DifferentialRevisionTestPlanTransaction.php',
     'DifferentialRevisionTitleHeraldField' => 'applications/differential/herald/DifferentialRevisionTitleHeraldField.php',
     'DifferentialRevisionTitleTransaction' => 'applications/differential/xaction/DifferentialRevisionTitleTransaction.php',
     'DifferentialRevisionTransactionType' => 'applications/differential/xaction/DifferentialRevisionTransactionType.php',
@@ -5206,6 +5207,7 @@
     'DifferentialRevisionStatus' => 'Phobject',
     'DifferentialRevisionSummaryHeraldField' => 'DifferentialRevisionHeraldField',
     'DifferentialRevisionSummaryTransaction' => 'DifferentialRevisionTransactionType',
+    'DifferentialRevisionTestPlanTransaction' => 'DifferentialRevisionTransactionType',
     'DifferentialRevisionTitleHeraldField' => 'DifferentialRevisionHeraldField',
     'DifferentialRevisionTitleTransaction' => 'DifferentialRevisionTransactionType',
     'DifferentialRevisionTransactionType' => 'PhabricatorModularTransactionType',
diff --git a/src/applications/differential/editor/DifferentialRevisionEditEngine.php b/src/applications/differential/editor/DifferentialRevisionEditEngine.php
--- a/src/applications/differential/editor/DifferentialRevisionEditEngine.php
+++ b/src/applications/differential/editor/DifferentialRevisionEditEngine.php
@@ -60,37 +60,70 @@
   }
 
   protected function buildCustomEditFields($object) {
-    return array(
-      id(new PhabricatorTextEditField())
-        ->setKey('title')
-        ->setLabel(pht('Title'))
-        ->setIsRequired(true)
-        ->setTransactionType(
-          DifferentialRevisionTitleTransaction::TRANSACTIONTYPE)
-        ->setDescription(pht('The title of the revision.'))
-        ->setConduitDescription(pht('Retitle the revision.'))
-        ->setConduitTypeDescription(pht('New revision title.'))
-        ->setValue($object->getTitle()),
-      id(new PhabricatorRemarkupEditField())
-        ->setKey('summary')
-        ->setLabel(pht('Summary'))
-        ->setTransactionType(
-          DifferentialRevisionSummaryTransaction::TRANSACTIONTYPE)
-        ->setDescription(pht('The summary of the revision.'))
-        ->setConduitDescription(pht('Change the revision summary.'))
-        ->setConduitTypeDescription(pht('New revision summary.'))
-        ->setValue($object->getSummary()),
-      id(new PhabricatorDatasourceEditField())
-        ->setKey('repositoryPHID')
-        ->setLabel(pht('Repository'))
-        ->setDatasource(new DiffusionRepositoryDatasource())
+
+    $plan_required = PhabricatorEnv::getEnvConfig(
+      'differential.require-test-plan-field');
+    $plan_enabled = $this->isCustomFieldEnabled(
+      $object,
+      'differential:test-plan');
+
+    $fields = array();
+    $fields[] = id(new PhabricatorTextEditField())
+      ->setKey('title')
+      ->setLabel(pht('Title'))
+      ->setIsRequired(true)
+      ->setTransactionType(
+        DifferentialRevisionTitleTransaction::TRANSACTIONTYPE)
+      ->setDescription(pht('The title of the revision.'))
+      ->setConduitDescription(pht('Retitle the revision.'))
+      ->setConduitTypeDescription(pht('New revision title.'))
+      ->setValue($object->getTitle());
+
+    $fields[] = id(new PhabricatorRemarkupEditField())
+      ->setKey('summary')
+      ->setLabel(pht('Summary'))
+      ->setTransactionType(
+        DifferentialRevisionSummaryTransaction::TRANSACTIONTYPE)
+      ->setDescription(pht('The summary of the revision.'))
+      ->setConduitDescription(pht('Change the revision summary.'))
+      ->setConduitTypeDescription(pht('New revision summary.'))
+      ->setValue($object->getSummary());
+
+    if ($plan_enabled) {
+      $fields[] = id(new PhabricatorRemarkupEditField())
+        ->setKey('testPlan')
+        ->setLabel(pht('Test Plan'))
+        ->setIsRequired($plan_required)
         ->setTransactionType(
-          DifferentialRevisionRepositoryTransaction::TRANSACTIONTYPE)
-        ->setDescription(pht('The repository the revision belongs to.'))
-        ->setConduitDescription(pht('Change the repository for this revision.'))
-        ->setConduitTypeDescription(pht('New repository.'))
-        ->setSingleValue($object->getRepositoryPHID()),
-    );
+          DifferentialRevisionTestPlanTransaction::TRANSACTIONTYPE)
+        ->setDescription(
+          pht('Actions performed to verify the behavior of the change.'))
+        ->setConduitDescription(pht('Update the revision test plan.'))
+        ->setConduitTypeDescription(pht('New test plan.'))
+        ->setValue($object->getTestPlan());
+    }
+
+    $fields[] = id(new PhabricatorDatasourceEditField())
+      ->setKey('repositoryPHID')
+      ->setLabel(pht('Repository'))
+      ->setDatasource(new DiffusionRepositoryDatasource())
+      ->setTransactionType(
+        DifferentialRevisionRepositoryTransaction::TRANSACTIONTYPE)
+      ->setDescription(pht('The repository the revision belongs to.'))
+      ->setConduitDescription(pht('Change the repository for this revision.'))
+      ->setConduitTypeDescription(pht('New repository.'))
+      ->setSingleValue($object->getRepositoryPHID());
+
+    return $fields;
+  }
+
+  private function isCustomFieldEnabled(DifferentialRevision $revision, $key) {
+    $field_list = PhabricatorCustomField::getObjectFields(
+      $revision,
+      PhabricatorCustomField::ROLE_EDIT);
+
+    $fields = $field_list->getFields();
+    return isset($fields[$key]);
   }
 
 }
diff --git a/src/applications/differential/xaction/DifferentialRevisionTestPlanTransaction.php b/src/applications/differential/xaction/DifferentialRevisionTestPlanTransaction.php
new file mode 100644
--- /dev/null
+++ b/src/applications/differential/xaction/DifferentialRevisionTestPlanTransaction.php
@@ -0,0 +1,74 @@
+<?php
+
+final class DifferentialRevisionTestPlanTransaction
+  extends DifferentialRevisionTransactionType {
+
+  const TRANSACTIONTYPE = 'differential.revision.testplan';
+
+  public function generateOldValue($object) {
+    return $object->getTestPlan();
+  }
+
+  public function applyInternalEffects($object, $value) {
+    $object->setTestPlan($value);
+  }
+
+  public function getTitle() {
+    return pht(
+      '%s edited the test plan for this revision.',
+      $this->renderAuthor());
+  }
+
+  public function getTitleForFeed() {
+    return pht(
+      '%s updated the test plan for %s.',
+      $this->renderAuthor(),
+      $this->renderObject());
+  }
+
+  public function hasChangeDetailView() {
+    return true;
+  }
+
+  public function getMailDiffSectionHeader() {
+    return pht('CHANGES TO TEST PLAN');
+  }
+
+  public function newChangeDetailView() {
+    $viewer = $this->getViewer();
+
+    return id(new PhabricatorApplicationTransactionTextDiffDetailView())
+      ->setViewer($viewer)
+      ->setOldText($this->getOldValue())
+      ->setNewText($this->getNewValue());
+  }
+
+  public function newRemarkupChanges() {
+    $changes = array();
+
+    $changes[] = $this->newRemarkupChange()
+      ->setOldValue($this->getOldValue())
+      ->setNewValue($this->getNewValue());
+
+    return $changes;
+  }
+
+  public function validateTransactions($object, array $xactions) {
+    $errors = array();
+
+    $is_required = PhabricatorEnv::getEnvConfig(
+      'differential.require-test-plan-field');
+
+    if ($is_required) {
+      if ($this->isEmptyTextTransaction($object->getTestPlan(), $xactions)) {
+        $errors[] = $this->newRequiredError(
+          pht(
+            'You must provide a test plan. Describe the actions you '.
+            'performed to verify the behavior of this change.'));
+      }
+    }
+
+    return $errors;
+  }
+
+}