diff --git a/src/nxt_conf_validation.c b/src/nxt_conf_validation.c
index 04091745c..80eb55cb9 100644
--- a/src/nxt_conf_validation.c
+++ b/src/nxt_conf_validation.c
@@ -176,6 +176,8 @@ static nxt_int_t nxt_conf_vldt_app_name(nxt_conf_validation_t *vldt,
     nxt_conf_value_t *value, void *data);
 static nxt_int_t nxt_conf_vldt_forwarded(nxt_conf_validation_t *vldt,
     nxt_conf_value_t *value, void *data);
+static nxt_int_t nxt_conf_vldt_listen_backlog(nxt_conf_validation_t *vldt,
+    nxt_conf_value_t *value, void *data);
 static nxt_int_t nxt_conf_vldt_app(nxt_conf_validation_t *vldt,
     nxt_str_t *name, nxt_conf_value_t *value);
 static nxt_int_t nxt_conf_vldt_object(nxt_conf_validation_t *vldt,
@@ -424,6 +426,10 @@ static nxt_conf_vldt_object_t  nxt_conf_vldt_listener_members[] = {
         .type       = NXT_CONF_VLDT_OBJECT,
         .validator  = nxt_conf_vldt_object,
         .u.members  = nxt_conf_vldt_client_ip_members
+    }, {
+        .name       = nxt_string("backlog"),
+        .type       = NXT_CONF_VLDT_NUMBER,
+        .validator  = nxt_conf_vldt_listen_backlog,
     },
 
 #if (NXT_TLS)
@@ -2677,6 +2683,32 @@ nxt_conf_vldt_forwarded(nxt_conf_validation_t *vldt, nxt_conf_value_t *value,
 }
 
 
+static nxt_int_t
+nxt_conf_vldt_listen_backlog(nxt_conf_validation_t *vldt,
+    nxt_conf_value_t *value, void *data)
+{
+    int64_t  backlog;
+
+    backlog = nxt_conf_get_number(value);
+
+    /*
+     * POSIX allows this to be 0 and some systems use -1 to
+     * indicate to use the OS's default value.
+     */
+    if (backlog < -1) {
+        return nxt_conf_vldt_error(vldt, "The \"backlog\" number must be "
+                                   "equal to or greater than -1.");
+    }
+
+    if (backlog > NXT_INT32_T_MAX) {
+        return nxt_conf_vldt_error(vldt, "The \"backlog\" number must "
+                                   "not exceed %d.", NXT_INT32_T_MAX);
+    }
+
+    return NXT_OK;
+}
+
+
 static nxt_int_t
 nxt_conf_vldt_app(nxt_conf_validation_t *vldt, nxt_str_t *name,
     nxt_conf_value_t *value)
diff --git a/src/nxt_router.c b/src/nxt_router.c
index 432094511..e4052d80b 100644
--- a/src/nxt_router.c
+++ b/src/nxt_router.c
@@ -166,7 +166,7 @@ static void nxt_router_app_prefork_ready(nxt_task_t *task,
 static void nxt_router_app_prefork_error(nxt_task_t *task,
     nxt_port_recv_msg_t *msg, void *data);
 static nxt_socket_conf_t *nxt_router_socket_conf(nxt_task_t *task,
-    nxt_router_temp_conf_t *tmcf, nxt_str_t *name);
+    nxt_router_temp_conf_t *tmcf, nxt_str_t *name, int backlog);
 static nxt_int_t nxt_router_listen_socket_find(nxt_router_temp_conf_t *tmcf,
     nxt_socket_conf_t *nskcf, nxt_sockaddr_t *sa);
 
@@ -1959,12 +1959,22 @@ nxt_router_conf_create(nxt_task_t *task, nxt_router_temp_conf_t *tmcf,
         next = 0;
 
         for ( ;; ) {
+            int               listen_backlog = -1;
+            nxt_conf_value_t  *backlog;
+
+            static const nxt_str_t  backlog_path = nxt_string("backlog");
+
             listener = nxt_conf_next_object_member(listeners, &name, &next);
             if (listener == NULL) {
                 break;
             }
 
-            skcf = nxt_router_socket_conf(task, tmcf, &name);
+            backlog = nxt_conf_get_object_member(listener, &backlog_path, NULL);
+            if (backlog != NULL) {
+                listen_backlog = nxt_conf_get_number(backlog);
+            }
+
+            skcf = nxt_router_socket_conf(task, tmcf, &name, listen_backlog);
             if (skcf == NULL) {
                 goto fail;
             }
@@ -2684,7 +2694,7 @@ nxt_router_application_init(nxt_router_conf_t *rtcf, nxt_str_t *name,
 
 static nxt_socket_conf_t *
 nxt_router_socket_conf(nxt_task_t *task, nxt_router_temp_conf_t *tmcf,
-    nxt_str_t *name)
+    nxt_str_t *name, int backlog)
 {
     size_t               size;
     nxt_int_t            ret;
@@ -2728,7 +2738,7 @@ nxt_router_socket_conf(nxt_task_t *task, nxt_router_temp_conf_t *tmcf,
         nxt_listen_socket_remote_size(ls);
 
         ls->socket = -1;
-        ls->backlog = NXT_LISTEN_BACKLOG;
+        ls->backlog = backlog > -1 ? backlog : NXT_LISTEN_BACKLOG;
         ls->flags = NXT_NONBLOCK;
         ls->read_after_accept = 1;
     }
@@ -2875,7 +2885,7 @@ nxt_router_listen_socket_ready(nxt_task_t *task, nxt_port_recv_msg_t *msg,
 
     nxt_socket_defer_accept(task, s, rpc->socket_conf->listen->sockaddr);
 
-    ret = nxt_listen_socket(task, s, NXT_LISTEN_BACKLOG);
+    ret = nxt_listen_socket(task, s, rpc->socket_conf->listen->backlog);
     if (nxt_slow_path(ret != NXT_OK)) {
         goto fail;
     }