diff --git a/Makefile.am b/Makefile.am
index f303e462..f2ac4aed 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -16,6 +16,7 @@ xdg_app_SOURCES = \
 	xdg-app-builtins.h \
 	xdg-app-builtins-add-repo.c \
 	xdg-app-builtins-install.c \
+	xdg-app-builtins-update.c \
 	xdg-app-dir.c \
 	xdg-app-dir.h \
 	xdg-app-utils.h \
diff --git a/xdg-app-builtins-update.c b/xdg-app-builtins-update.c
new file mode 100644
index 00000000..91af946c
--- /dev/null
+++ b/xdg-app-builtins-update.c
@@ -0,0 +1,91 @@
+#include "config.h"
+
+#include <locale.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "libgsystem.h"
+
+#include "xdg-app-builtins.h"
+#include "xdg-app-utils.h"
+
+static char *opt_arch;
+
+static GOptionEntry options[] = {
+  { "arch", 0, 0, G_OPTION_ARG_STRING, &opt_arch, "Arch to update for", NULL },
+  { NULL }
+};
+
+static void
+usage_error (GOptionContext *context, const char *message, GError **error)
+{
+  gs_free gchar *help = g_option_context_get_help (context, TRUE, NULL);
+  g_printerr ("%s", help);
+  g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED, message);
+}
+
+gboolean
+xdg_app_builtin_update_runtime (int argc, char **argv, GCancellable *cancellable, GError **error)
+{
+  gboolean ret = FALSE;
+  GOptionContext *context;
+  gs_unref_object XdgAppDir *dir = NULL;
+  gs_unref_object GFile *deploy_base = NULL;
+  gs_unref_object GFile *origin = NULL;
+  const char *runtime;
+  const char *branch = "master";
+  gs_free char *ref = NULL;
+  gs_free char *repository = NULL;
+  GError *my_error;
+
+  context = g_option_context_new ("RUNTIME [BRANCH] - Update a runtime");
+
+  if (!xdg_app_option_context_parse (context, options, &argc, &argv, 0, &dir, cancellable, error))
+    goto out;
+
+  if (argc < 3)
+    {
+      usage_error (context, "REPOSITORY and RUNTIME must be specified", error);
+      goto out;
+    }
+
+  runtime  = argv[1];
+  if (argc >= 3)
+    branch = argv[2];
+
+  ref = xdg_app_build_runtime_ref (runtime, branch, opt_arch);
+
+  deploy_base = xdg_app_dir_get_deploy_dir (dir, ref);
+  if (!g_file_query_exists (deploy_base, cancellable))
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED, "Runtime %s branch %s not installed", runtime, branch);
+      goto out;
+    }
+
+  origin = g_file_get_child (deploy_base, "origin");
+  if (!g_file_load_contents (origin, cancellable, &repository, NULL, NULL, error))
+    goto out;
+
+  if (!xdg_app_dir_pull (dir, repository, ref,
+                         cancellable, error))
+    goto out;
+
+  my_error = NULL;
+  if (!xdg_app_dir_deploy (dir, ref, NULL, cancellable, &my_error))
+    {
+      if (g_error_matches (my_error, XDG_APP_DIR_ERROR, XDG_APP_DIR_ERROR_ALREADY_DEPLOYED))
+        g_error_free (my_error);
+      else
+        {
+          g_propagate_error (error, my_error);
+          goto out;
+        }
+    }
+
+  ret = TRUE;
+ out:
+  if (context)
+    g_option_context_free (context);
+  return ret;
+}
diff --git a/xdg-app-builtins.h b/xdg-app-builtins.h
index 66e2a6fb..bc8ea34c 100644
--- a/xdg-app-builtins.h
+++ b/xdg-app-builtins.h
@@ -26,6 +26,7 @@ gboolean xdg_app_option_context_parse (GOptionContext *context,
 
 BUILTINPROTO(add_repo);
 BUILTINPROTO(install_runtime);
+BUILTINPROTO(update_runtime);
 
 #undef BUILTINPROTO
 
diff --git a/xdg-app-main.c b/xdg-app-main.c
index 24a7f721..9258f45c 100644
--- a/xdg-app-main.c
+++ b/xdg-app-main.c
@@ -21,6 +21,7 @@ typedef struct {
 static XdgAppCommand commands[] = {
   { "add-repo", xdg_app_builtin_add_repo },
   { "install-runtime", xdg_app_builtin_install_runtime },
+  { "update-runtime", xdg_app_builtin_update_runtime },
   { NULL }
 };