diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1a02ae4..c528fe4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 * Add minimal captcha module
 * Add minimal support/contact form
 * Add captcha to registrations
+* Blacklist misleading username for new accounts
 
 # management 0.2.0, 2021-01-19
 
diff --git a/lib/recycledcloud/accounts/user.ex b/lib/recycledcloud/accounts/user.ex
index bf2fb6a..d77b2fb 100644
--- a/lib/recycledcloud/accounts/user.ex
+++ b/lib/recycledcloud/accounts/user.ex
@@ -186,8 +186,18 @@ defmodule RecycledCloud.Accounts.User do
   end
 
   defp validate_username(changeset) do
+    check_blacklist = fn changeset ->
+      username = get_field(changeset, :username)
+      if TheBigUsernameBlacklist.valid?(username) do
+        changeset
+      else
+        add_error(changeset, :username, "This username is blacklisted, you cannot use it.")
+      end
+    end
+
     changeset
     |> validate_required([:username])
+    |> check_blacklist.()
   end
 
   @doc """
diff --git a/mix.exs b/mix.exs
index 2eb6e03..d2fb779 100644
--- a/mix.exs
+++ b/mix.exs
@@ -60,7 +60,8 @@ defmodule RecycledCloud.MixProject do
       # FIXME: See https://github.com/gen-smtp/gen_smtp/issues/234
       {:ranch, "~> 1.7.1", override: true},
       {:xmlrpc, "~> 1.4"},
-      {:httpoison, "~> 1.8"}
+      {:httpoison, "~> 1.8"},
+      {:the_big_username_blacklist, "~> 0.1"}
     ]
   end
 
diff --git a/mix.lock b/mix.lock
index 56dd822..fc83e9f 100644
--- a/mix.lock
+++ b/mix.lock
@@ -41,6 +41,7 @@
   "telemetry": {:hex, :telemetry, "0.4.2", "2808c992455e08d6177322f14d3bdb6b625fbcfd233a73505870d8738a2f4599", [:rebar3], [], "hexpm", "2d1419bd9dda6a206d7b5852179511722e2b18812310d304620c7bd92a13fcef"},
   "telemetry_metrics": {:hex, :telemetry_metrics, "0.6.0", "da9d49ee7e6bb1c259d36ce6539cd45ae14d81247a2b0c90edf55e2b50507f7b", [:mix], [{:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "5cfe67ad464b243835512aa44321cee91faed6ea868d7fb761d7016e02915c3d"},
   "telemetry_poller": {:hex, :telemetry_poller, "0.5.1", "21071cc2e536810bac5628b935521ff3e28f0303e770951158c73eaaa01e962a", [:rebar3], [{:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "4cab72069210bc6e7a080cec9afffad1b33370149ed5d379b81c7c5f0c663fd4"},
+  "the_big_username_blacklist": {:hex, :the_big_username_blacklist, "0.1.2", "a2622f06a26279c9cd5216ada872c2dceb63bc2ade5c8714df0de65a24aa985c", [:mix], [], "hexpm", "9f411601209758d4a5ef9e247a1e7b908c0cd05e78171f51f07e68b7afb038fe"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"},
   "xmlrpc": {:hex, :xmlrpc, "1.4.1", "e69711f5a15b297c6c27dd833726a6a0cf06bab9130ac6039b8031510a3af497", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:erlsom, "~> 1.4", [hex: :erlsom, repo: "hexpm", optional: false]}], "hexpm", "4680ce0e452f80ce69f405429fa35ecfbd5a385fe882a7f2666702da3cd173a7"},
 }