diff --git a/lib/pleroma/user.ex b/lib/pleroma/user.ex
index 9da67498..a290db04 100644
--- a/lib/pleroma/user.ex
+++ b/lib/pleroma/user.ex
@@ -2,6 +2,7 @@ defmodule Pleroma.User do
   use Ecto.Schema
 
   import Ecto.{Changeset, Query}
+  alias Ecto.Multi
   alias Pleroma.{Repo, User, Object, Web, Activity, Notification}
   alias Comeonin.Pbkdf2
   alias Pleroma.Formatter
@@ -23,6 +24,7 @@ defmodule Pleroma.User do
     field(:local, :boolean, default: true)
     field(:follower_address, :string)
     field(:search_distance, :float, virtual: true)
+    field(:tags, {:array, :string}, default: [])
     field(:last_refreshed_at, :naive_datetime)
     has_many(:notifications, Notification)
     embeds_one(:info, Pleroma.User.Info)
@@ -815,4 +817,41 @@ defmodule Pleroma.User do
 
     CommonUtils.format_input(bio, mentions, tags, "text/plain") |> Formatter.emojify(emoji)
   end
+
+  def tag(user_identifiers, tags) when is_list(user_identifiers) do
+    Repo.transaction(fn ->
+      for user_identifier <- user_identifiers, do: tag(user_identifier, tags)
+    end)
+  end
+
+  def untag(user_identifiers, tags) when is_list(user_identifiers) do
+    Repo.transaction(fn ->
+      for user_identifier <- user_identifiers, do: untag(user_identifier, tags)
+    end)
+  end
+
+  def tag(nickname, tags) when is_binary(nickname), do: tag(User.get_by_nickname(nickname), tags)
+
+  def untag(nickname, tags) when is_binary(nickname),
+    do: untag(User.get_by_nickname(nickname), tags)
+
+  def tag(%User{} = user, tags),
+    do: update_tags(user, Enum.uniq(user.tags ++ normalize_tags(tags)))
+
+  def untag(%User{} = user, tags), do: update_tags(user, user.tags -- normalize_tags(tags))
+
+  defp update_tags(%User{} = user, new_tags) do
+    {:ok, updated_user} =
+      user
+      |> change(%{tags: new_tags})
+      |> Repo.update()
+
+    updated_user
+  end
+
+  defp normalize_tags(tags) do
+    [tags]
+    |> List.flatten()
+    |> Enum.map(&String.downcase(&1))
+  end
 end
diff --git a/lib/pleroma/web/admin_api/admin_api_controller.ex b/lib/pleroma/web/admin_api/admin_api_controller.ex
index 2c67d9cd..0bd85e0b 100644
--- a/lib/pleroma/web/admin_api/admin_api_controller.ex
+++ b/lib/pleroma/web/admin_api/admin_api_controller.ex
@@ -3,6 +3,8 @@ defmodule Pleroma.Web.AdminAPI.AdminAPIController do
   alias Pleroma.{User, Repo}
   alias Pleroma.Web.ActivityPub.Relay
 
+  import Pleroma.Web.ControllerHelper, only: [json_response: 3]
+
   require Logger
 
   action_fallback(:errors)
@@ -40,6 +42,16 @@ defmodule Pleroma.Web.AdminAPI.AdminAPIController do
     |> json(new_user.nickname)
   end
 
+  def tag_users(conn, %{"nicknames" => nicknames, "tags" => tags}) do
+    with {:ok, _} <- User.tag(nicknames, tags),
+         do: json_response(conn, :no_content, "")
+  end
+
+  def untag_users(conn, %{"nicknames" => nicknames, "tags" => tags}) do
+    with {:ok, _} <- User.untag(nicknames, tags),
+         do: json_response(conn, :no_content, "")
+  end
+
   def right_add(conn, %{"permission_group" => permission_group, "nickname" => nickname})
       when permission_group in ["moderator", "admin"] do
     user = User.get_by_nickname(nickname)
diff --git a/lib/pleroma/web/controller_helper.ex b/lib/pleroma/web/controller_helper.ex
new file mode 100644
index 00000000..ddf95881
--- /dev/null
+++ b/lib/pleroma/web/controller_helper.ex
@@ -0,0 +1,9 @@
+defmodule Pleroma.Web.ControllerHelper do
+  use Pleroma.Web, :controller
+
+  def json_response(conn, status, json) do
+    conn
+    |> put_status(status)
+    |> json(json)
+  end
+end
diff --git a/lib/pleroma/web/mastodon_api/views/account_view.ex b/lib/pleroma/web/mastodon_api/views/account_view.ex
index bcfa8836..ebcf9230 100644
--- a/lib/pleroma/web/mastodon_api/views/account_view.ex
+++ b/lib/pleroma/web/mastodon_api/views/account_view.ex
@@ -58,6 +58,11 @@ defmodule Pleroma.Web.MastodonAPI.AccountView do
         note: "",
         privacy: user_info.default_scope,
         sensitive: false
+      },
+
+      # Pleroma extension
+      pleroma: %{
+        tags: user.tags
       }
     }
   end
diff --git a/lib/pleroma/web/router.ex b/lib/pleroma/web/router.ex
index 75d965c6..4d24d4c1 100644
--- a/lib/pleroma/web/router.ex
+++ b/lib/pleroma/web/router.ex
@@ -98,6 +98,8 @@ defmodule Pleroma.Web.Router do
     pipe_through(:admin_api)
     delete("/user", AdminAPIController, :user_delete)
     post("/user", AdminAPIController, :user_create)
+    put("/users/tag", AdminAPIController, :tag_users)
+    delete("/users/tag", AdminAPIController, :untag_users)
 
     get("/permission_group/:nickname", AdminAPIController, :right_get)
     get("/permission_group/:nickname/:permission_group", AdminAPIController, :right_get)
diff --git a/lib/pleroma/web/twitter_api/views/user_view.ex b/lib/pleroma/web/twitter_api/views/user_view.ex
index b78024ed..b3459af9 100644
--- a/lib/pleroma/web/twitter_api/views/user_view.ex
+++ b/lib/pleroma/web/twitter_api/views/user_view.ex
@@ -77,7 +77,12 @@ defmodule Pleroma.Web.TwitterAPI.UserView do
       "locked" => user.info.locked,
       "default_scope" => user.info.default_scope,
       "no_rich_text" => user.info.no_rich_text,
-      "fields" => fields
+      "fields" => fields,
+
+      # Pleroma extension
+      "pleroma" => %{
+        "tags" => user.tags
+      }
     }
 
     if assigns[:token] do
diff --git a/priv/repo/migrations/20181206125616_add_tags_to_users.exs b/priv/repo/migrations/20181206125616_add_tags_to_users.exs
new file mode 100644
index 00000000..1502f63b
--- /dev/null
+++ b/priv/repo/migrations/20181206125616_add_tags_to_users.exs
@@ -0,0 +1,11 @@
+defmodule Pleroma.Repo.Migrations.AddTagsToUsers do
+  use Ecto.Migration
+
+  def change do
+    alter table(:users) do
+      add :tags, {:array, :string}
+    end
+
+    create index(:users, [:tags], using: :gin)
+  end
+end
diff --git a/test/web/admin_api/admin_api_controller_test.exs b/test/web/admin_api/admin_api_controller_test.exs
index 9634ad7c..ba3b77fb 100644
--- a/test/web/admin_api/admin_api_controller_test.exs
+++ b/test/web/admin_api/admin_api_controller_test.exs
@@ -37,6 +37,78 @@ defmodule Pleroma.Web.AdminAPI.AdminAPIControllerTest do
     end
   end
 
+  describe "PUT /api/pleroma/admin/users/tag" do
+    setup do
+      admin = insert(:user, info: %{is_admin: true})
+      user1 = insert(:user, %{tags: ["x"]})
+      user2 = insert(:user, %{tags: ["y"]})
+      user3 = insert(:user, %{tags: ["unchanged"]})
+
+      conn =
+        build_conn()
+        |> assign(:user, admin)
+        |> put_req_header("accept", "application/json")
+        |> put(
+          "/api/pleroma/admin/users/tag?nicknames[]=#{user1.nickname}&nicknames[]=#{
+            user2.nickname
+          }&tags[]=foo&tags[]=bar"
+        )
+
+      %{conn: conn, user1: user1, user2: user2, user3: user3}
+    end
+
+    test "it appends specified tags to users with specified nicknames", %{
+      conn: conn,
+      user1: user1,
+      user2: user2
+    } do
+      assert json_response(conn, :no_content)
+      assert Repo.get(User, user1.id).tags == ["x", "foo", "bar"]
+      assert Repo.get(User, user2.id).tags == ["y", "foo", "bar"]
+    end
+
+    test "it does not modify tags of not specified users", %{conn: conn, user3: user3} do
+      assert json_response(conn, :no_content)
+      assert Repo.get(User, user3.id).tags == ["unchanged"]
+    end
+  end
+
+  describe "DELETE /api/pleroma/admin/users/tag" do
+    setup do
+      admin = insert(:user, info: %{is_admin: true})
+      user1 = insert(:user, %{tags: ["x"]})
+      user2 = insert(:user, %{tags: ["y", "z"]})
+      user3 = insert(:user, %{tags: ["unchanged"]})
+
+      conn =
+        build_conn()
+        |> assign(:user, admin)
+        |> put_req_header("accept", "application/json")
+        |> delete(
+          "/api/pleroma/admin/users/tag?nicknames[]=#{user1.nickname}&nicknames[]=#{
+            user2.nickname
+          }&tags[]=x&tags[]=z"
+        )
+
+      %{conn: conn, user1: user1, user2: user2, user3: user3}
+    end
+
+    test "it removes specified tags from users with specified nicknames", %{
+      conn: conn,
+      user1: user1,
+      user2: user2
+    } do
+      assert json_response(conn, :no_content)
+      assert Repo.get(User, user1.id).tags == []
+      assert Repo.get(User, user2.id).tags == ["y"]
+    end
+
+    test "it does not modify tags of not specified users", %{conn: conn, user3: user3} do
+      assert json_response(conn, :no_content)
+      assert Repo.get(User, user3.id).tags == ["unchanged"]
+    end
+  end
+
   describe "/api/pleroma/admin/permission_group" do
     test "GET is giving user_info" do
       admin = insert(:user, info: %{is_admin: true})
diff --git a/test/web/mastodon_api/account_view_test.exs b/test/web/mastodon_api/account_view_test.exs
index a2d3a254..3cb9b9c5 100644
--- a/test/web/mastodon_api/account_view_test.exs
+++ b/test/web/mastodon_api/account_view_test.exs
@@ -54,7 +54,8 @@ defmodule Pleroma.Web.MastodonAPI.AccountViewTest do
         note: "",
         privacy: "public",
         sensitive: false
-      }
+      },
+      pleroma: %{tags: []}
     }
 
     assert expected == AccountView.render("account.json", %{user: user})
@@ -91,7 +92,8 @@ defmodule Pleroma.Web.MastodonAPI.AccountViewTest do
         note: "",
         privacy: "public",
         sensitive: false
-      }
+      },
+      pleroma: %{tags: []}
     }
 
     assert expected == AccountView.render("account.json", %{user: user})
diff --git a/test/web/twitter_api/views/user_view_test.exs b/test/web/twitter_api/views/user_view_test.exs
index e69ca24a..9898c217 100644
--- a/test/web/twitter_api/views/user_view_test.exs
+++ b/test/web/twitter_api/views/user_view_test.exs
@@ -96,7 +96,8 @@ defmodule Pleroma.Web.TwitterAPI.UserViewTest do
       "locked" => false,
       "default_scope" => "public",
       "no_rich_text" => false,
-      "fields" => []
+      "fields" => [],
+      "pleroma" => %{"tags" => []}
     }
 
     assert represented == UserView.render("show.json", %{user: user})
@@ -137,7 +138,8 @@ defmodule Pleroma.Web.TwitterAPI.UserViewTest do
       "locked" => false,
       "default_scope" => "public",
       "no_rich_text" => false,
-      "fields" => []
+      "fields" => [],
+      "pleroma" => %{"tags" => []}
     }
 
     assert represented == UserView.render("show.json", %{user: user, for: follower})
@@ -179,7 +181,8 @@ defmodule Pleroma.Web.TwitterAPI.UserViewTest do
       "locked" => false,
       "default_scope" => "public",
       "no_rich_text" => false,
-      "fields" => []
+      "fields" => [],
+      "pleroma" => %{"tags" => []}
     }
 
     assert represented == UserView.render("show.json", %{user: follower, for: user})
@@ -228,7 +231,8 @@ defmodule Pleroma.Web.TwitterAPI.UserViewTest do
       "locked" => false,
       "default_scope" => "public",
       "no_rich_text" => false,
-      "fields" => []
+      "fields" => [],
+      "pleroma" => %{"tags" => []}
     }
 
     blocker = Repo.get(User, blocker.id)