diff --git a/man/kernel-command-line.xml b/man/kernel-command-line.xml
index 211ae5ac57..479b482a30 100644
--- a/man/kernel-command-line.xml
+++ b/man/kernel-command-line.xml
@@ -423,6 +423,16 @@
         </listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>systemd.default_device_timeout_sec=</varname></term>
+
+        <listitem>
+          <para>Overrides the default device timeout <varname>DefaultDeviceTimeoutSec=</varname> at boot. For
+          details, see
+          <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+        </listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><varname>systemd.watchdog_device=</varname></term>
 
diff --git a/src/core/main.c b/src/core/main.c
index c69f9b9afe..3eb53577eb 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -400,6 +400,18 @@ static int parse_proc_cmdline_item(const char *key, const char *value, void *dat
                 if (arg_default_timeout_start_usec <= 0)
                         arg_default_timeout_start_usec = USEC_INFINITY;
 
+        } else if (proc_cmdline_key_streq(key, "systemd.default_device_timeout_sec")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                r = parse_sec(value, &arg_default_device_timeout_usec);
+                if (r < 0)
+                        log_warning_errno(r, "Failed to parse default device timeout '%s', ignoring: %m", value);
+
+                if (arg_default_device_timeout_usec <= 0)
+                        arg_default_device_timeout_usec = USEC_INFINITY;
+
         } else if (proc_cmdline_key_streq(key, "systemd.cpu_affinity")) {
 
                 if (proc_cmdline_value_missing(key, value))