diff --git a/resources/sql/autopatches/20180418.almanac.network.unique.php b/resources/sql/autopatches/20180418.almanac.network.unique.php
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20180418.almanac.network.unique.php
@@ -0,0 +1,46 @@
+<?php
+
+$table = new AlmanacNetwork();
+$conn = $table->establishConnection('w');
+
+queryfx(
+  $conn,
+  'LOCK TABLES %T WRITE',
+  $table->getTableName());
+
+$seen = array();
+foreach (new LiskMigrationIterator($table) as $network) {
+  $name = $network->getName();
+
+  // If this is the first copy of this row we've seen, mark it as seen and
+  // move on.
+  if (empty($seen[$name])) {
+    $seen[$name] = 1;
+    continue;
+  }
+
+  // Otherwise, rename this row.
+  while (true) {
+    $new_name = $name.'-'.$seen[$name];
+    if (empty($seen[$new_name])) {
+      $network->setName($new_name);
+      try {
+        $network->save();
+        break;
+      } catch (AphrontDuplicateKeyQueryException $ex) {
+        // New name is a dupe of a network we haven't seen yet.
+      }
+    }
+    $seen[$name]++;
+  }
+  $seen[$new_name] = 1;
+}
+
+queryfx(
+  $conn,
+  'ALTER TABLE %T ADD UNIQUE KEY `key_name` (name)',
+  $table->getTableName());
+
+queryfx(
+  $conn,
+  'UNLOCK TABLES');
diff --git a/src/applications/almanac/query/AlmanacNetworkQuery.php b/src/applications/almanac/query/AlmanacNetworkQuery.php
--- a/src/applications/almanac/query/AlmanacNetworkQuery.php
+++ b/src/applications/almanac/query/AlmanacNetworkQuery.php
@@ -5,6 +5,7 @@
 
   private $ids;
   private $phids;
+  private $names;
 
   public function withIDs(array $ids) {
     $this->ids = $ids;
@@ -20,6 +21,11 @@
     return new AlmanacNetwork();
   }
 
+  public function withNames(array $names) {
+    $this->names = $names;
+    return $this;
+  }
+
   public function withNameNgrams($ngrams) {
     return $this->withNgramsConstraint(
       new AlmanacNetworkNameNgrams(),
@@ -47,6 +53,13 @@
         $this->phids);
     }
 
+    if ($this->names !== null) {
+      $where[] = qsprintf(
+        $conn,
+        'network.name IN (%Ls)',
+        $this->names);
+    }
+
     return $where;
   }
 
diff --git a/src/applications/almanac/storage/AlmanacNetwork.php b/src/applications/almanac/storage/AlmanacNetwork.php
--- a/src/applications/almanac/storage/AlmanacNetwork.php
+++ b/src/applications/almanac/storage/AlmanacNetwork.php
@@ -24,8 +24,15 @@
     return array(
       self::CONFIG_AUX_PHID => true,
       self::CONFIG_COLUMN_SCHEMA => array(
-        'name' => 'text128',
+        'name' => 'sort128',
         'mailKey' => 'bytes20',
+
+      ),
+      self::CONFIG_KEY_SCHEMA => array(
+        'key_name' => array(
+            'columns' => array('name'),
+            'unique' => true,
+          ),
       ),
     ) + parent::getConfiguration();
   }
diff --git a/src/applications/almanac/util/AlmanacNames.php b/src/applications/almanac/util/AlmanacNames.php
--- a/src/applications/almanac/util/AlmanacNames.php
+++ b/src/applications/almanac/util/AlmanacNames.php
@@ -6,57 +6,58 @@
     if (strlen($name) < 3) {
       throw new Exception(
         pht(
-          'Almanac service, device, property and namespace names must be '.
-          'at least 3 characters long.'));
+          'Almanac service, device, property, network and namespace names '.
+          'must be at least 3 characters long.'));
     }
 
     if (strlen($name) > 100) {
       throw new Exception(
         pht(
-          'Almanac service, device, property and namespace names may not '.
-          'be more than 100 characters long.'));
+          'Almanac service, device, property, network and namespace names '.
+          'may not be more than 100 characters long.'));
     }
 
     if (!preg_match('/^[a-z0-9.-]+\z/', $name)) {
       throw new Exception(
         pht(
-          'Almanac service, device, property and namespace names may only '.
-          'contain lowercase letters, numbers, hyphens, and periods.'));
+          'Almanac service, device, property, network and namespace names '.
+          'may only contain lowercase letters, numbers, hyphens, and '.
+          'periods.'));
     }
 
     if (preg_match('/(^|\\.)\d+(\z|\\.)/', $name)) {
       throw new Exception(
         pht(
-          'Almanac service, device, property and namespace names may not '.
-          'have any segments containing only digits.'));
+          'Almanac service, device, network, property and namespace names '.
+          'may not have any segments containing only digits.'));
     }
 
     if (preg_match('/\.\./', $name)) {
       throw new Exception(
         pht(
-          'Almanac service, device, property and namespace names may not '.
-          'contain multiple consecutive periods.'));
+          'Almanac service, device, property, network and namespace names '.
+          'may not contain multiple consecutive periods.'));
     }
 
     if (preg_match('/\\.-|-\\./', $name)) {
       throw new Exception(
         pht(
-          'Almanac service, device, property and namespace names may not '.
-          'contain hyphens adjacent to periods.'));
+          'Almanac service, device, property, network and namespace names '.
+          'may not contain hyphens adjacent to periods.'));
     }
 
     if (preg_match('/--/', $name)) {
       throw new Exception(
         pht(
-          'Almanac service, device, property and namespace names may not '.
-          'contain multiple consecutive hyphens.'));
+          'Almanac service, device, property, network and namespace names '.
+          'may not contain multiple consecutive hyphens.'));
     }
 
     if (!preg_match('/^[a-z0-9].*[a-z0-9]\z/', $name)) {
       throw new Exception(
         pht(
-          'Almanac service, device, property and namespace names must begin '.
-          'and end with a letter or number.'));
+          'Almanac service, device, property, network and namespace names '.
+          'must begin and end with a letter or number.'));
     }
   }
 
diff --git a/src/applications/almanac/xaction/AlmanacNetworkNameTransaction.php b/src/applications/almanac/xaction/AlmanacNetworkNameTransaction.php
--- a/src/applications/almanac/xaction/AlmanacNetworkNameTransaction.php
+++ b/src/applications/almanac/xaction/AlmanacNetworkNameTransaction.php
@@ -38,6 +38,37 @@
         pht('Network name is required.'));
     }
 
+    foreach ($xactions as $xaction) {
+      $name = $xaction->getNewValue();
+
+      $message = null;
+      try {
+        AlmanacNames::validateName($name);
+      } catch (Exception $ex) {
+        $message = $ex->getMessage();
+      }
+
+      if ($message !== null) {
+        $errors[] = $this->newInvalidError($message, $xaction);
+        continue;
+      }
+
+      if ($name === $object->getName()) {
+        continue;
+      }
+
+      $other = id(new AlmanacNetworkQuery())
+        ->setViewer(PhabricatorUser::getOmnipotentUser())
+        ->withNames(array($name))
+        ->executeOne();
+      if ($other && ($other->getID() != $object->getID())) {
+        $errors[] = $this->newInvalidError(
+          pht('Almanac networks must have unique names.'),
+          $xaction);
+        continue;
+      }
+    }
+
     return $errors;
   }