diff --git a/ryu/app/rest_qos.py b/ryu/app/rest_qos.py
index c5bac29a..ee3d45f4 100644
--- a/ryu/app/rest_qos.py
+++ b/ryu/app/rest_qos.py
@@ -1147,13 +1147,13 @@ class Action(object):
         if REST_ACTION in flow:
             actions = []
             for act in flow[REST_ACTION]:
-                field_value = re.search('SET_FIELD: \{ip_dscp:(\d+)', act)
+                field_value = re.search(r'SET_FIELD: \{ip_dscp:(\d+)', act)
                 if field_value:
                     actions.append({REST_ACTION_MARK: field_value.group(1)})
-                meter_value = re.search('METER:(\d+)', act)
+                meter_value = re.search(r'METER:(\d+)', act)
                 if meter_value:
                     actions.append({REST_ACTION_METER: meter_value.group(1)})
-                queue_value = re.search('SET_QUEUE:(\d+)', act)
+                queue_value = re.search(r'SET_QUEUE:(\d+)', act)
                 if queue_value:
                     actions.append({REST_ACTION_QUEUE: queue_value.group(1)})
             action = {REST_ACTION: actions}
diff --git a/ryu/lib/ofctl_string.py b/ryu/lib/ofctl_string.py
index 30394c65..fe0eeaea 100644
--- a/ryu/lib/ofctl_string.py
+++ b/ryu/lib/ofctl_string.py
@@ -39,7 +39,7 @@ def ofp_instruction_from_str(ofproto, action_str):
     action_str  An action string.
     =========== =================================================
     """
-    action_re = re.compile("([a-z_]+)(\([^)]*\)|[^a-z_,()][^,()]*)*")
+    action_re = re.compile(r"([a-z_]+)(\([^)]*\)|[^a-z_,()][^,()]*)*")
     result = []
     while len(action_str):
         m = action_re.match(action_str)
@@ -303,7 +303,7 @@ class OfctlActionConverter(object):
                     if k == 'table':
                         recirc_table = str_to_int(v)
                     elif k == 'zone':
-                        m = re.search('\[(\d*)\.\.(\d*)\]', v)
+                        m = re.search(r'\[(\d*)\.\.(\d*)\]', v)
                         if m:
                             zone_ofs_nbits = nicira_ext.ofs_nbits(
                                 int(m.group(1)), int(m.group(2)))
diff --git a/ryu/lib/ovs/vsctl.py b/ryu/lib/ovs/vsctl.py
index f3355a1c..53ee7f42 100644
--- a/ryu/lib/ovs/vsctl.py
+++ b/ryu/lib/ovs/vsctl.py
@@ -66,12 +66,12 @@ def valid_ovsdb_addr(addr):
     :return: True if valid, otherwise False.
     """
     # Assumes Unix socket format: "unix:file"
-    m = re.match('unix:(\S+)', addr)
+    m = re.match(r'unix:(\S+)', addr)
     if m:
         file = m.group(1)
         return os.path.isfile(file)
     # Assumes TCP/SSL socket format: "tcp:ip:port" or "ssl:ip:port"
-    m = re.match('(tcp|ssl):(\S+):(\d+)', addr)
+    m = re.match(r'(tcp|ssl):(\S+):(\d+)', addr)
     if m:
         address = m.group(2)
         port = m.group(3)
diff --git a/ryu/lib/packet/bmp.py b/ryu/lib/packet/bmp.py
index bc49c577..0b4c3b84 100644
--- a/ryu/lib/packet/bmp.py
+++ b/ryu/lib/packet/bmp.py
@@ -69,7 +69,7 @@ BMP_PEER_DOWN_REASON_REMOTE_NO_NOTIFICATION = 4
 
 
 class BMPMessage(packet_base.PacketBase, TypeDisp):
-    """Base class for BGP Monitoring Protocol messages.
+    r"""Base class for BGP Monitoring Protocol messages.
 
     An instance has the following attributes at least.
     Most of them are same to the on-wire counterparts but in host byte
@@ -141,7 +141,7 @@ class BMPMessage(packet_base.PacketBase, TypeDisp):
 
 
 class BMPPeerMessage(BMPMessage):
-    """BMP Message with Per Peer Header
+    r"""BMP Message with Per Peer Header
 
     Following BMP Messages contain Per Peer Header after Common BMP Header.
 
@@ -250,7 +250,7 @@ class BMPPeerMessage(BMPMessage):
 
 @BMPMessage.register_type(BMP_MSG_ROUTE_MONITORING)
 class BMPRouteMonitoring(BMPPeerMessage):
-    """BMP Route Monitoring Message
+    r"""BMP Route Monitoring Message
 
     ========================== ===============================================
     Attribute                  Description
@@ -308,7 +308,7 @@ class BMPRouteMonitoring(BMPPeerMessage):
 
 @BMPMessage.register_type(BMP_MSG_STATISTICS_REPORT)
 class BMPStatisticsReport(BMPPeerMessage):
-    """BMP Statistics Report Message
+    r"""BMP Statistics Report Message
 
     ========================== ===============================================
     Attribute                  Description
@@ -424,7 +424,7 @@ class BMPStatisticsReport(BMPPeerMessage):
 
 @BMPMessage.register_type(BMP_MSG_PEER_DOWN_NOTIFICATION)
 class BMPPeerDownNotification(BMPPeerMessage):
-    """BMP Peer Down Notification Message
+    r"""BMP Peer Down Notification Message
 
     ========================== ===============================================
     Attribute                  Description
@@ -498,7 +498,7 @@ class BMPPeerDownNotification(BMPPeerMessage):
 
 @BMPMessage.register_type(BMP_MSG_PEER_UP_NOTIFICATION)
 class BMPPeerUpNotification(BMPPeerMessage):
-    """BMP Peer Up Notification Message
+    r"""BMP Peer Up Notification Message
 
     ========================== ===============================================
     Attribute                  Description
@@ -605,7 +605,7 @@ class BMPPeerUpNotification(BMPPeerMessage):
 
 @BMPMessage.register_type(BMP_MSG_INITIATION)
 class BMPInitiation(BMPMessage):
-    """BMP Initiation Message
+    r"""BMP Initiation Message
 
     ========================== ===============================================
     Attribute                  Description
@@ -669,7 +669,7 @@ class BMPInitiation(BMPMessage):
 
 @BMPMessage.register_type(BMP_MSG_TERMINATION)
 class BMPTermination(BMPMessage):
-    """BMP Termination Message
+    r"""BMP Termination Message
 
     ========================== ===============================================
     Attribute                  Description
diff --git a/ryu/lib/packet/icmpv6.py b/ryu/lib/packet/icmpv6.py
index 00b883bf..a391c087 100644
--- a/ryu/lib/packet/icmpv6.py
+++ b/ryu/lib/packet/icmpv6.py
@@ -75,7 +75,7 @@ BLOCK_OLD_SOURCES = 6
 
 
 class icmpv6(packet_base.PacketBase):
-    """ICMPv6 (RFC 2463) header encoder/decoder class.
+    r"""ICMPv6 (RFC 2463) header encoder/decoder class.
 
     An instance has the following attributes at least.
     Most of them are same to the on-wire counterparts but in host byte order.
@@ -553,7 +553,7 @@ class nd_option_tla(nd_option_la):
 
 @nd_router_advert.register_nd_option_type
 class nd_option_pi(nd_option):
-    """ICMPv6 sub encoder/decoder class for Neighbor discovery
+    r"""ICMPv6 sub encoder/decoder class for Neighbor discovery
     Prefix Information Option. (RFC 4861)
 
     This is used with ryu.lib.packet.icmpv6.nd_router_advert.
@@ -884,7 +884,7 @@ class mldv2_report(mld):
 
 
 class mldv2_report_group(stringify.StringifyMixin):
-    """
+    r"""
     ICMPv6 sub encoder/decoder class for MLD v2 Lister Report Group
     Record messages. (RFC 3810)
 
diff --git a/ryu/lib/packet/igmp.py b/ryu/lib/packet/igmp.py
index 8935da3b..d4c9552c 100644
--- a/ryu/lib/packet/igmp.py
+++ b/ryu/lib/packet/igmp.py
@@ -391,7 +391,7 @@ class igmpv3_report(igmp):
 
 
 class igmpv3_report_group(stringify.StringifyMixin):
-    """
+    r"""
     Internet Group Management Protocol(IGMP, RFC 3376)
     Membership Report Group Record message encoder/decoder class.
 
diff --git a/ryu/lib/packet/ipv6.py b/ryu/lib/packet/ipv6.py
index 007dc564..6ceaced3 100644
--- a/ryu/lib/packet/ipv6.py
+++ b/ryu/lib/packet/ipv6.py
@@ -274,7 +274,7 @@ class dst_opts(opt_header):
 
 
 class option(stringify.StringifyMixin):
-    """IPv6 (RFC 2460) Options header encoder/decoder class.
+    r"""IPv6 (RFC 2460) Options header encoder/decoder class.
 
     This is used with ryu.lib.packet.ipv6.hop_opts or
                       ryu.lib.packet.ipv6.dst_opts.
@@ -496,7 +496,7 @@ class routing_type3(header):
 
 @ipv6.register_header_type(inet.IPPROTO_FRAGMENT)
 class fragment(header):
-    """IPv6 (RFC 2460) fragment header encoder/decoder class.
+    r"""IPv6 (RFC 2460) fragment header encoder/decoder class.
 
     This is used with ryu.lib.packet.ipv6.ipv6.
 
diff --git a/ryu/lib/stringify.py b/ryu/lib/stringify.py
index 94ffbbcb..e178408b 100644
--- a/ryu/lib/stringify.py
+++ b/ryu/lib/stringify.py
@@ -327,7 +327,7 @@ class StringifyMixin(object):
     @classmethod
     def from_jsondict(cls, dict_, decode_string=base64.b64decode,
                       **additional_args):
-        """Create an instance from a JSON style dict.
+        r"""Create an instance from a JSON style dict.
 
         Instantiate this class with parameters specified by the dict.
 
diff --git a/ryu/ofproto/nicira_ext.py b/ryu/ofproto/nicira_ext.py
index 73297cfb..9ac673a3 100644
--- a/ryu/ofproto/nicira_ext.py
+++ b/ryu/ofproto/nicira_ext.py
@@ -298,7 +298,7 @@ NXM_IP_FRAG_NOT_LATER = (0, FLOW_NW_FRAG_LATER)
 
 
 def ofs_nbits(start, end):
-    """
+    r"""
     The utility method for ofs_nbits
 
     This method is used in the class to set the ofs_nbits.
diff --git a/ryu/ofproto/nx_actions.py b/ryu/ofproto/nx_actions.py
index ae5c48f4..5fe0d545 100644
--- a/ryu/ofproto/nx_actions.py
+++ b/ryu/ofproto/nx_actions.py
@@ -248,7 +248,7 @@ def generate(ofp_name, ofpp_name):
 
     # For OpenFlow1.0 only
     class NXActionSetQueue(NXAction):
-        """
+        r"""
         Set queue action
 
         This action sets the queue that should be used to queue
@@ -338,7 +338,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionRegLoad(NXAction):
-        """
+        r"""
         Load literal value action
 
         This action loads a literal value into a field or part of a field.
@@ -405,7 +405,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionRegLoad2(NXAction):
-        """
+        r"""
         Load literal value action
 
         This action loads a literal value into a field or part of a field.
@@ -474,7 +474,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionNote(NXAction):
-        """
+        r"""
         Note action
 
         This action does nothing at all.
@@ -553,7 +553,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionSetTunnel(_NXActionSetTunnelBase):
-        """
+        r"""
         Set Tunnel action
 
         This action sets the identifier (such as GRE) to the specified id.
@@ -600,7 +600,7 @@ def generate(ofp_name, ofpp_name):
         _fmt_str = '!2xI'
 
     class NXActionSetTunnel64(_NXActionSetTunnelBase):
-        """
+        r"""
         Set Tunnel action
 
         This action outputs to a port that encapsulates
@@ -648,7 +648,7 @@ def generate(ofp_name, ofpp_name):
         _fmt_str = '!6xQ'
 
     class NXActionRegMove(NXAction):
-        """
+        r"""
         Move register action
 
         This action copies the src to dst.
@@ -737,7 +737,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionResubmit(NXAction):
-        """
+        r"""
         Resubmit action
 
         This action searches one of the switch's flow tables.
@@ -786,7 +786,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionResubmitTable(NXAction):
-        """
+        r"""
         Resubmit action
 
         This action searches one of the switch's flow tables.
@@ -840,7 +840,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionOutputReg(NXAction):
-        """
+        r"""
         Add output action
 
         This action outputs the packet to the OpenFlow port number read from
@@ -914,7 +914,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionOutputReg2(NXAction):
-        """
+        r"""
         Add output action
 
         This action outputs the packet to the OpenFlow port number read from
@@ -996,7 +996,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionLearn(NXAction):
-        """
+        r"""
         Adds or modifies flow action
 
         This action adds or modifies a flow in OpenFlow table.
@@ -1260,7 +1260,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionController(NXAction):
-        """
+        r"""
         Send packet in message action
 
         This action sends the packet to the OpenFlow controller as
@@ -1325,7 +1325,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionController2(NXAction):
-        """
+        r"""
         Send packet in message action
 
         This action sends the packet to the OpenFlow controller as
@@ -1571,7 +1571,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionDecTtlCntIds(NXAction):
-        """
+        r"""
         Decrement TTL action
 
         This action decrements TTL of IPv4 packet or
@@ -1682,7 +1682,7 @@ def generate(ofp_name, ofpp_name):
 
     # For OpenFlow1.0 only
     class NXActionPushMpls(NXActionMplsBase):
-        """
+        r"""
         Push MPLS action
 
         This action pushes a new MPLS header to the packet.
@@ -1717,7 +1717,7 @@ def generate(ofp_name, ofpp_name):
 
     # For OpenFlow1.0 only
     class NXActionPopMpls(NXActionMplsBase):
-        """
+        r"""
         Pop MPLS action
 
         This action pops the MPLS header from the packet.
@@ -1752,7 +1752,7 @@ def generate(ofp_name, ofpp_name):
 
     # For OpenFlow1.0 only
     class NXActionSetMplsTtl(NXAction):
-        """
+        r"""
         Set MPLS TTL action
 
         This action sets the MPLS TTL.
@@ -1851,7 +1851,7 @@ def generate(ofp_name, ofpp_name):
 
     # For OpenFlow1.0 only
     class NXActionSetMplsLabel(NXAction):
-        """
+        r"""
         Set MPLS Lavel action
 
         This action sets the MPLS Label.
@@ -1906,7 +1906,7 @@ def generate(ofp_name, ofpp_name):
 
     # For OpenFlow1.0 only
     class NXActionSetMplsTc(NXAction):
-        """
+        r"""
         Set MPLS Tc action
 
         This action sets the MPLS Tc.
@@ -2000,7 +2000,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionStackPush(NXActionStackBase):
-        """
+        r"""
         Push field action
 
         This action pushes field to top of the stack.
@@ -2032,7 +2032,7 @@ def generate(ofp_name, ofpp_name):
         _subtype = nicira_ext.NXAST_STACK_PUSH
 
     class NXActionStackPop(NXActionStackBase):
-        """
+        r"""
         Pop field action
 
         This action pops field from top of the stack.
@@ -2064,7 +2064,7 @@ def generate(ofp_name, ofpp_name):
         _subtype = nicira_ext.NXAST_STACK_POP
 
     class NXActionSample(NXAction):
-        """
+        r"""
         Sample packets action
 
         This action samples packets and sends one sample for
@@ -2137,7 +2137,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionSample2(NXAction):
-        """
+        r"""
         Sample packets action
 
         This action samples packets and sends one sample for
@@ -2218,7 +2218,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionFinTimeout(NXAction):
-        """
+        r"""
         Change TCP timeout action
 
         This action changes the idle timeout or hard timeout or
@@ -2279,7 +2279,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionConjunction(NXAction):
-        """
+        r"""
         Conjunctive matches action
 
         This action ties groups of individual OpenFlow flows into
@@ -2342,7 +2342,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionMultipath(NXAction):
-        """
+        r"""
         Select multipath link action
 
         This action selects multipath link based on the specified parameters.
@@ -2528,7 +2528,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionBundle(_NXActionBundleBase):
-        """
+        r"""
         Select bundle link action
 
         This action selects bundle link based on the specified parameters.
@@ -2581,7 +2581,7 @@ def generate(ofp_name, ofpp_name):
                 ofs_nbits=0, dst=0, slaves=slaves)
 
     class NXActionBundleLoad(_NXActionBundleBase):
-        """
+        r"""
         Select bundle link action
 
         This action has the same behavior as the bundle action,
@@ -2642,7 +2642,7 @@ def generate(ofp_name, ofpp_name):
                 ofs_nbits, dst, slaves)
 
     class NXActionCT(NXAction):
-        """
+        r"""
         Pass traffic to the connection tracker action
 
         This action sends the packet through the connection tracker.
@@ -2804,7 +2804,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionNAT(NXAction):
-        """
+        r"""
         Network address translation action
 
         This action sends the packet through the connection tracker.
@@ -2967,7 +2967,7 @@ def generate(ofp_name, ofpp_name):
             return data
 
     class NXActionOutputTrunc(NXAction):
-        """
+        r"""
         Truncate output action
 
         This action truncate a packet into the specified size and outputs it.
diff --git a/ryu/tests/integrated/test_vrrp_linux_multi.py b/ryu/tests/integrated/test_vrrp_linux_multi.py
index dca70c47..ac5c3252 100644
--- a/ryu/tests/integrated/test_vrrp_linux_multi.py
+++ b/ryu/tests/integrated/test_vrrp_linux_multi.py
@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""
+r"""
 Usage:
 PYTHONPATH=. ./bin/ryu-manager --verbose \
              ryu.services.protocols.vrrp.dumper \
diff --git a/ryu/tests/integrated/test_vrrp_multi.py b/ryu/tests/integrated/test_vrrp_multi.py
index 6aee6395..a26d949a 100644
--- a/ryu/tests/integrated/test_vrrp_multi.py
+++ b/ryu/tests/integrated/test_vrrp_multi.py
@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""
+r"""
 Usage:
 PYTHONPATH=. ./bin/ryu-manager --verbose \
              ryu.topology.switches \
diff --git a/ryu/tests/packet_data_generator3/gen.py b/ryu/tests/packet_data_generator3/gen.py
index dca45cf9..7f2fbeef 100644
--- a/ryu/tests/packet_data_generator3/gen.py
+++ b/ryu/tests/packet_data_generator3/gen.py
@@ -319,7 +319,7 @@ if __name__ == '__main__':
                                    stdout=subprocess.PIPE)
     has_names = False
     try:
-        ver_tuple = re.search('\s(\d+)\.(\d+)(\.\d*|\s*$)',
+        ver_tuple = re.search(r'\s(\d+)\.(\d+)(\.\d*|\s*$)',
                               ovs_version.stdout.readline().decode()).groups()
         if int(ver_tuple[0]) > 2 or \
            int(ver_tuple[0]) == 2 and int(ver_tuple[1]) >= 8: