diff --git a/manifests/init.pp b/manifests/init.pp
index b65ed22c..dfcc1363 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -349,12 +349,18 @@
 #    Defaults to undef
 #
 #  [*session_timeout*]
-#    (optional) The session timeout for horizon in seconds. After this many seconds of inactivity
-#    the user is logged out.
+#    (optional) The session timeout for horizon in seconds. After this many
+#    seconds of inactivity the user is logged out.
 #    Defaults to 3600.
 #
+#  [*simultaneous_sessions*]
+#    (optional) Controls whether a user can have multiple simultaneous
+#    sessions.
+#    Defaults to undef
+#
 #  [*token_timeout_margin*]
-#    (optional) A time margin in seconds to subtract from the real token's validity.
+#    (optional) A time margin in seconds to subtract from the real token's
+#    validity.
 #    Defaults to 0.
 #
 #  [*timezone*]
@@ -622,6 +628,7 @@ class horizon(
   $access_log_format                                = undef,
   $session_timeout                                  = 3600,
   $token_timeout_margin                             = 0,
+  $simultaneous_sessions                            = undef,
   $timezone                                         = 'UTC',
   Boolean $secure_cookies                           = false,
   $django_session_engine                            = undef,
diff --git a/releasenotes/notes/simultaneous_sessions-c503feb527139590.yaml b/releasenotes/notes/simultaneous_sessions-c503feb527139590.yaml
new file mode 100644
index 00000000..343e698b
--- /dev/null
+++ b/releasenotes/notes/simultaneous_sessions-c503feb527139590.yaml
@@ -0,0 +1,4 @@
+---
+features:
+  - |
+    The new ``horizon::simultaneous_sessions`` parameter has been added.
diff --git a/spec/classes/horizon_init_spec.rb b/spec/classes/horizon_init_spec.rb
index cf566a46..2ca88857 100644
--- a/spec/classes/horizon_init_spec.rb
+++ b/spec/classes/horizon_init_spec.rb
@@ -129,6 +129,7 @@ describe 'horizon' do
           :keystone_default_domain          => 'domain.tld',
           :overview_days_range              => 1,
           :session_timeout                  => 1800,
+          :simultaneous_sessions            => 'allow',
           :token_timeout_margin             => 60,
           :timezone                         => 'Asia/Shanghai',
           :available_themes                 => [
@@ -218,6 +219,7 @@ describe 'horizon' do
           "            'level': 'DEBUG',",
           "            'handlers': ['console', 'syslog'],",
           'SESSION_TIMEOUT = 1800',
+          "SIMULTANEOUS_SESSIONS = 'allow'",
           'TOKEN_TIMEOUT_MARGIN = 60',
           'COMPRESS_ENABLED = False',
           'COMPRESS_OFFLINE = False',
diff --git a/templates/local_settings.py.erb b/templates/local_settings.py.erb
index 22675e5a..fa914bf4 100644
--- a/templates/local_settings.py.erb
+++ b/templates/local_settings.py.erb
@@ -1048,6 +1048,11 @@ SECURITY_GROUP_RULES = {
 }
 
 SESSION_TIMEOUT = <%= @session_timeout %>
+<% if ! @simultaneous_sessions.nil? -%>
+# Control whether a same user can have multiple action sessions.
+#SIMULTANEOUS_SESSIONS = 'allow'
+SIMULTANEOUS_SESSIONS = '<%= @simultaneous_sessions %>'
+<% end -%>
 
 TOKEN_TIMEOUT_MARGIN = <%= @token_timeout_margin %>