diff --git a/devstack/lib/l2_agent b/devstack/lib/l2_agent
index 0e7b8401072..28afe525146 100644
--- a/devstack/lib/l2_agent
+++ b/devstack/lib/l2_agent
@@ -1,13 +1,3 @@
-function plugin_agent_add_l2_agent_extension {
-    local l2_agent_extension=$1
-    if [[ -z "$L2_AGENT_EXTENSIONS" ]]; then
-        L2_AGENT_EXTENSIONS=$l2_agent_extension
-    elif [[ ! ,${L2_AGENT_EXTENSIONS}, =~ ,${l2_agent_extension}, ]]; then
-        L2_AGENT_EXTENSIONS+=",$l2_agent_extension"
-    fi
-}
-
-
 function configure_l2_agent {
     iniset /$NEUTRON_CORE_PLUGIN_CONF agent extensions "$L2_AGENT_EXTENSIONS"
 }
diff --git a/devstack/lib/l3_agent b/devstack/lib/l3_agent
index 080a91a576e..3342c5a3692 100644
--- a/devstack/lib/l3_agent
+++ b/devstack/lib/l3_agent
@@ -1,13 +1,3 @@
-function plugin_agent_add_l3_agent_extension {
-    local l3_agent_extension=$1
-    if [[ -z "$L3_AGENT_EXTENSIONS" ]]; then
-        L3_AGENT_EXTENSIONS=$l3_agent_extension
-    elif [[ ! ,${L3_AGENT_EXTENSIONS}, =~ ,${l3_agent_extension}, ]]; then
-        L3_AGENT_EXTENSIONS+=",$l3_agent_extension"
-    fi
-}
-
-
 function configure_l3_agent {
     iniset $NEUTRON_L3_CONF agent extensions "$L3_AGENT_EXTENSIONS"
 }
diff --git a/devstack/lib/ml2 b/devstack/lib/ml2
index c4ccd0b01f7..a5b55bd08c5 100644
--- a/devstack/lib/ml2
+++ b/devstack/lib/ml2
@@ -1,8 +1,3 @@
-function configure_qos_ml2 {
-    neutron_ml2_extension_driver_add "qos"
-}
-
-
 function configure_ml2_extension_drivers {
     if is_neutron_legacy_enabled; then
         # NOTE(yamamoto): This overwrites what neutron-legacy set,
diff --git a/devstack/lib/qos b/devstack/lib/qos
deleted file mode 100644
index 9570fc74802..00000000000
--- a/devstack/lib/qos
+++ /dev/null
@@ -1,28 +0,0 @@
-function configure_qos_service_plugin {
-    neutron_service_plugin_class_add "qos"
-}
-
-
-function configure_qos_core_plugin {
-    configure_qos_$NEUTRON_CORE_PLUGIN
-}
-
-
-function configure_qos_l2_agent {
-    plugin_agent_add_l2_agent_extension "qos"
-}
-
-
-function configure_qos {
-    configure_qos_service_plugin
-    configure_qos_core_plugin
-    configure_qos_l2_agent
-}
-
-function configure_l3_agent_extension_fip_qos {
-    plugin_agent_add_l3_agent_extension "fip_qos"
-}
-
-function configure_l3_agent_extension_gateway_ip_qos {
-    plugin_agent_add_l3_agent_extension "gateway_ip_qos"
-}
diff --git a/devstack/plugin.sh b/devstack/plugin.sh
index 156e3503974..7d51ad0e3be 100644
--- a/devstack/plugin.sh
+++ b/devstack/plugin.sh
@@ -9,7 +9,6 @@ source $LIBDIR/l3_agent
 source $LIBDIR/l3_conntrack_helper
 source $LIBDIR/ml2
 source $LIBDIR/network_segment_range
-source $LIBDIR/qos
 source $LIBDIR/segments
 source $LIBDIR/log
 source $LIBDIR/fip_port_forwarding
@@ -53,9 +52,6 @@ if [[ "$1" == "stack" ]]; then
             if is_service_enabled q-flavors neutron-flavors; then
                 configure_flavors
             fi
-            if is_service_enabled q-qos neutron-qos; then
-                configure_qos
-            fi
             if is_service_enabled q-log neutron-log; then
                 configure_log
             fi
@@ -90,10 +86,6 @@ if [[ "$1" == "stack" ]]; then
                 configure_l2_agent_sriovnicswitch
             fi
             if is_service_enabled q-l3 neutron-l3; then
-                if is_service_enabled q-qos neutron-qos; then
-                    configure_l3_agent_extension_fip_qos
-                    configure_l3_agent_extension_gateway_ip_qos
-                fi
                 if is_service_enabled q-port-forwarding neutron-port-forwarding; then
                     configure_port_forwarding
                 fi