diff --git a/man/systemd.journal-fields.xml b/man/systemd.journal-fields.xml
index 197a468f25..31e3d8b210 100644
--- a/man/systemd.journal-fields.xml
+++ b/man/systemd.journal-fields.xml
@@ -149,6 +149,13 @@
           <literal>file:/</literal>, <literal>man:</literal> or <literal>info:</literal> URL.</para>
         </listitem>
       </varlistentry>
+
+      <varlistentry>
+        <term><varname>TID=</varname></term>
+        <listitem>
+          <para>The numeric thread ID (TID) the log message originates from.</para>
+        </listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 
diff --git a/src/basic/log.c b/src/basic/log.c
index 89d26a4a43..7c68258ea8 100644
--- a/src/basic/log.c
+++ b/src/basic/log.c
@@ -547,6 +547,7 @@ static int log_do_header(
         r = snprintf(header, size,
                      "PRIORITY=%i\n"
                      "SYSLOG_FACILITY=%i\n"
+                     "TID=" PID_FMT "\n"
                      "%s%.256s%s"        /* CODE_FILE */
                      "%s%.*i%s"          /* CODE_LINE */
                      "%s%.256s%s"        /* CODE_FUNC */
@@ -556,6 +557,7 @@ static int log_do_header(
                      "SYSLOG_IDENTIFIER=%.256s\n",
                      LOG_PRI(level),
                      LOG_FAC(level),
+                     gettid(),
                      isempty(file) ? "" : "CODE_FILE=",
                      isempty(file) ? "" : file,
                      isempty(file) ? "" : "\n",