diff --git a/Documentation/config-gerrit.txt b/Documentation/config-gerrit.txt
index 9eded88..8ad5b9d 100644
--- a/Documentation/config-gerrit.txt
+++ b/Documentation/config-gerrit.txt
@@ -2317,6 +2317,25 @@
 +
 By default unset.
 
+[[gerrit.installIndexModule]]gerrit.installIndexModule::
++
+Class name of the Guice modules to load as alternate implementation
+for the Gerrit indexes backend.
+Classes are resolved using the primary Gerrit class loader, hence the
+class needs to be either declared in Gerrit or an additional JAR
+located under the `/lib` directory.
++
+NOTE: The `gerrit.installIndexModule` has precedence over the
+`index.type`.
++
+By default unset.
++
+Example:
+----
+[gerrit]
+  installIndexModule = com.google.gerrit.elasticsearch.ElasticIndexModule
+----
++
 [[gerrit.installModule]]gerrit.installModule::
 +
 Repeatable list of class name of additional Guice modules to load at
@@ -3136,16 +3155,13 @@
 
 [[index.type]]index.type::
 +
-Type of secondary indexing employed by Gerrit.  The supported
-values are:
+*(DEPRECATED)* The only supported value is `LUCENE`, which is the default,
+that means a link:http://lucene.apache.org/[Lucene]
+index is used.
 +
-* `LUCENE`
+For using other indexing backends (e.g. ElasticSearch), refer to
+`gerrit.installIndexModule` setting.
 +
-A link:http://lucene.apache.org/[Lucene] index is used.
-+
-+
-By default, `LUCENE`.
-
 [[index.threads]]index.threads::
 +
 Number of threads to use for indexing in normal interactive operations. Setting
diff --git a/java/com/google/gerrit/pgm/Daemon.java b/java/com/google/gerrit/pgm/Daemon.java
index 1668018..d77daa1 100644
--- a/java/com/google/gerrit/pgm/Daemon.java
+++ b/java/com/google/gerrit/pgm/Daemon.java
@@ -524,6 +524,7 @@
 
     List<Module> libModules =
         LibModuleLoader.loadModules(cfgInjector, LibModuleType.SYS_MODULE_TYPE);
+    libModules.addAll(LibModuleLoader.loadModules(cfgInjector, LibModuleType.INDEX_MODULE_TYPE));
     libModules.addAll(testSysModules);
 
     AuthConfig authConfig = cfgInjector.getInstance(AuthConfig.class);
diff --git a/java/com/google/gerrit/pgm/Reindex.java b/java/com/google/gerrit/pgm/Reindex.java
index b4b5ffb..69c7d6f 100644
--- a/java/com/google/gerrit/pgm/Reindex.java
+++ b/java/com/google/gerrit/pgm/Reindex.java
@@ -30,6 +30,8 @@
 import com.google.gerrit.lucene.LuceneIndexModule;
 import com.google.gerrit.pgm.util.BatchProgramModule;
 import com.google.gerrit.pgm.util.SiteProgram;
+import com.google.gerrit.server.LibModuleLoader;
+import com.google.gerrit.server.ModuleOverloader;
 import com.google.gerrit.server.cache.CacheDisplay;
 import com.google.gerrit.server.cache.CacheInfo;
 import com.google.gerrit.server.change.ChangeResource;
@@ -207,7 +209,9 @@
           }
         });
 
-    return dbInjector.createChildInjector(modules);
+    return dbInjector.createChildInjector(
+        ModuleOverloader.override(
+            modules, LibModuleLoader.loadReindexModules(cfgInjector, versions, threads, replica)));
   }
 
   private void overrideConfig() {
diff --git a/java/com/google/gerrit/server/LibModuleLoader.java b/java/com/google/gerrit/server/LibModuleLoader.java
index 0a6fb9f..36765e9 100644
--- a/java/com/google/gerrit/server/LibModuleLoader.java
+++ b/java/com/google/gerrit/server/LibModuleLoader.java
@@ -22,8 +22,10 @@
 import com.google.inject.Key;
 import com.google.inject.Module;
 import com.google.inject.ProvisionException;
+import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
 import org.eclipse.jgit.lib.Config;
 
 /** Loads configured Guice modules from {@code gerrit.installModule}. */
@@ -37,6 +39,33 @@
         .collect(toList());
   }
 
+  public static List<Module> loadReindexModules(
+      Injector parent, Map<String, Integer> versions, int threads, boolean replica) {
+    Config cfg = getConfig(parent);
+    return Arrays.stream(
+            cfg.getStringList(
+                "gerrit", null, "install" + LibModuleType.INDEX_MODULE_TYPE.getConfigKey()))
+        .map(m -> createReindexModule(m, versions, threads, replica))
+        .collect(toList());
+  }
+
+  private static Module createReindexModule(
+      String className, Map<String, Integer> versions, int threads, boolean replica) {
+    Class<Module> clazz = loadModule(className);
+    try {
+
+      Method m =
+          clazz.getMethod("singleVersionWithExplicitVersions", Map.class, int.class, boolean.class);
+
+      Module module = (Module) m.invoke(null, versions, threads, replica);
+      logger.atInfo().log("Installed module %s", className);
+      return module;
+    } catch (Exception e) {
+      logger.atSevere().withCause(e).log("Unable to load libModule for %s", className);
+      throw new IllegalStateException(e);
+    }
+  }
+
   private static Config getConfig(Injector i) {
     return i.getInstance(Key.get(Config.class, GerritServerConfig.class));
   }
diff --git a/java/com/google/gerrit/server/LibModuleType.java b/java/com/google/gerrit/server/LibModuleType.java
index 4c70ce7..57206aa 100644
--- a/java/com/google/gerrit/server/LibModuleType.java
+++ b/java/com/google/gerrit/server/LibModuleType.java
@@ -24,7 +24,10 @@
   SYS_BATCH_MODULE_TYPE("BatchModule"),
 
   /** Module for the dbInjector. */
-  DB_MODULE_TYPE("DbModule");
+  DB_MODULE_TYPE("DbModule"),
+
+  /** Module for the implementation of the indexing backend. */
+  INDEX_MODULE_TYPE("IndexModule");
 
   private final String configKey;