diff --git a/Makefile.am b/Makefile.am
index 2093ac23..68dd8ae3 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -159,6 +159,7 @@ test_run_tests_SOURCES = test/blackhole-server.c \
                          test/test-close-fd.c \
                          test/test-close-order.c \
                          test/test-condvar.c \
+                         test/test-connect-unspecified.c \
                          test/test-connection-fail.c \
                          test/test-cwd-and-chdir.c \
                          test/test-default-loop-close.c \
diff --git a/docs/src/tcp.rst b/docs/src/tcp.rst
index a1a58245..e761b460 100644
--- a/docs/src/tcp.rst
+++ b/docs/src/tcp.rst
@@ -102,7 +102,14 @@ API
     and an uninitialized :c:type:`uv_connect_t`. `addr` should point to an
     initialized ``struct sockaddr_in`` or ``struct sockaddr_in6``.
 
+    On Windows if the `addr` is initialized to point to an unspecified address
+    (``0.0.0.0`` or ``::``) it will be changed to point to ``localhost``.
+    This is done to match the behavior of Linux systems.
+
     The callback is made when the connection has been established or when a
     connection error happened.
 
+    .. versionchanged:: 1.19.0 added ``0.0.0.0`` and ``::`` to ``localhost``
+        mapping
+
 .. seealso:: The :c:type:`uv_stream_t` API functions also apply.
diff --git a/docs/src/udp.rst b/docs/src/udp.rst
index 8704a099..81488285 100644
--- a/docs/src/udp.rst
+++ b/docs/src/udp.rst
@@ -243,6 +243,10 @@ API
     with :c:func:`uv_udp_bind` it will be bound to 0.0.0.0
     (the "all interfaces" IPv4 address) and a random port number.
 
+    On Windows if the `addr` is initialized to point to an unspecified address
+    (``0.0.0.0`` or ``::``) it will be changed to point to ``localhost``.
+    This is done to match the behavior of Linux systems.
+
     :param req: UDP request handle. Need not be initialized.
 
     :param handle: UDP handle. Should have been initialized with
@@ -259,6 +263,9 @@ API
 
     :returns: 0 on success, or an error code < 0 on failure.
 
+    .. versionchanged:: 1.19.0 added ``0.0.0.0`` and ``::`` to ``localhost``
+        mapping
+
 .. c:function:: int uv_udp_try_send(uv_udp_t* handle, const uv_buf_t bufs[], unsigned int nbufs, const struct sockaddr* addr)
 
     Same as :c:func:`uv_udp_send`, but won't queue a send request if it can't
diff --git a/src/win/tcp.c b/src/win/tcp.c
index e63a63e7..fd6efbaf 100644
--- a/src/win/tcp.c
+++ b/src/win/tcp.c
@@ -747,10 +747,15 @@ static int uv_tcp_try_connect(uv_connect_t* req,
                               uv_connect_cb cb) {
   uv_loop_t* loop = handle->loop;
   const struct sockaddr* bind_addr;
+  struct sockaddr_storage converted;
   BOOL success;
   DWORD bytes;
   int err;
 
+  err = uv__convert_to_localhost_if_unspecified(addr, &converted);
+  if (err)
+    return err;
+
   if (handle->delayed_error) {
     return handle->delayed_error;
   }
@@ -782,12 +787,12 @@ static int uv_tcp_try_connect(uv_connect_t* req,
   memset(&req->u.io.overlapped, 0, sizeof(req->u.io.overlapped));
 
   success = handle->tcp.conn.func_connectex(handle->socket,
-                                           addr,
-                                           addrlen,
-                                           NULL,
-                                           0,
-                                           &bytes,
-                                           &req->u.io.overlapped);
+                                            (const struct sockaddr*) &converted,
+                                            addrlen,
+                                            NULL,
+                                            0,
+                                            &bytes,
+                                            &req->u.io.overlapped);
 
   if (UV_SUCCEEDED_WITHOUT_IOCP(success)) {
     /* Process the req without IOCP. */
diff --git a/src/win/udp.c b/src/win/udp.c
index 21348f37..cd1d0e07 100644
--- a/src/win/udp.c
+++ b/src/win/udp.c
@@ -923,10 +923,15 @@ int uv__udp_try_send(uv_udp_t* handle,
                      unsigned int addrlen) {
   DWORD bytes;
   const struct sockaddr* bind_addr;
+  struct sockaddr_storage converted;
   int err;
 
   assert(nbufs > 0);
 
+  err = uv__convert_to_localhost_if_unspecified(addr, &converted);
+  if (err)
+    return err;
+
   /* Already sending a message.*/
   if (handle->send_queue_count != 0)
     return UV_EAGAIN;
@@ -948,7 +953,7 @@ int uv__udp_try_send(uv_udp_t* handle,
                   nbufs,
                   &bytes,
                   0,
-                  addr,
+                  (const struct sockaddr*) &converted,
                   addrlen,
                   NULL,
                   NULL);
diff --git a/src/win/winsock.c b/src/win/winsock.c
index e86d76b1..7cfa90f8 100644
--- a/src/win/winsock.c
+++ b/src/win/winsock.c
@@ -559,3 +559,31 @@ int WSAAPI uv_msafd_poll(SOCKET socket, AFD_POLL_INFO* info_in,
     return SOCKET_ERROR;
   }
 }
+
+int uv__convert_to_localhost_if_unspecified(const struct sockaddr* addr,
+                                            struct sockaddr_storage* storage) {
+  struct sockaddr_in* dest4;
+  struct sockaddr_in6* dest6;
+
+  if (addr == NULL)
+    return UV_EINVAL;
+
+  switch (addr->sa_family) {
+  case AF_INET:
+    dest4 = (struct sockaddr_in*) storage;
+    memcpy(dest4, addr, sizeof(*dest4));
+    if (dest4->sin_addr.s_addr == 0)
+      dest4->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+    return 0;
+  case AF_INET6:
+    dest6 = (struct sockaddr_in6*) storage;
+    memcpy(dest6, addr, sizeof(*dest6));
+    if (memcmp(&dest6->sin6_addr,
+               &uv_addr_ip6_any_.sin6_addr,
+               sizeof(uv_addr_ip6_any_.sin6_addr)) == 0)
+      dest6->sin6_addr = (struct in6_addr) IN6ADDR_LOOPBACK_INIT;
+    return 0;
+  default:
+    return UV_EINVAL;
+  }
+}
diff --git a/src/win/winsock.h b/src/win/winsock.h
index 7c007ab4..7ecb755b 100644
--- a/src/win/winsock.h
+++ b/src/win/winsock.h
@@ -187,4 +187,7 @@ typedef struct _IP_ADAPTER_UNICAST_ADDRESS_LH {
 
 #endif
 
+int uv__convert_to_localhost_if_unspecified(const struct sockaddr* addr,
+                                            struct sockaddr_storage* storage);
+
 #endif /* UV_WIN_WINSOCK_H_ */
diff --git a/test/test-connect-unspecified.c b/test/test-connect-unspecified.c
new file mode 100644
index 00000000..04e1c8a5
--- /dev/null
+++ b/test/test-connect-unspecified.c
@@ -0,0 +1,61 @@
+/* Copyright libuv project contributors. All rights reserved.
+*
+* Permission is hereby granted, free of charge, to any person obtaining a copy
+* of this software and associated documentation files (the "Software"), to
+* deal in the Software without restriction, including without limitation the
+* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+* sell copies of the Software, and to permit persons to whom the Software is
+* furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+* IN THE SOFTWARE.
+*/
+
+#include "uv.h"
+#include "task.h"
+
+static void connect_4(uv_connect_t* req, int status) {
+  ASSERT(status != UV_EADDRNOTAVAIL);
+}
+
+static void connect_6(uv_connect_t* req, int status) {
+  ASSERT(status != UV_EADDRNOTAVAIL);
+}
+
+TEST_IMPL(connect_unspecified) {
+  uv_loop_t* loop;
+  uv_tcp_t socket4;
+  struct sockaddr_in addr4;
+  uv_connect_t connect4;
+  uv_tcp_t socket6;
+  struct sockaddr_in6 addr6;
+  uv_connect_t connect6;
+
+  loop = uv_default_loop();
+
+  ASSERT(uv_tcp_init(loop, &socket4) == 0);
+  ASSERT(uv_ip4_addr("0.0.0.0", TEST_PORT, &addr4) == 0);
+  ASSERT(uv_tcp_connect(&connect4,
+                        &socket4,
+                        (const struct sockaddr*) &addr4,
+                        connect_4) == 0);
+
+  ASSERT(uv_tcp_init(loop, &socket6) == 0);
+  ASSERT(uv_ip6_addr("::", TEST_PORT, &addr6) == 0);
+  ASSERT(uv_tcp_connect(&connect6,
+                        &socket6,
+                        (const struct sockaddr*) &addr6,
+                        connect_6) == 0);
+
+  ASSERT(uv_run(loop, UV_RUN_DEFAULT) == 0);
+
+  return 0;
+}
diff --git a/test/test-list.h b/test/test-list.h
index c1a17803..6af1b64f 100644
--- a/test/test-list.h
+++ b/test/test-list.h
@@ -55,6 +55,7 @@ TEST_DECLARE   (tty_file)
 TEST_DECLARE   (tty_pty)
 TEST_DECLARE   (stdio_over_pipes)
 TEST_DECLARE   (ip6_pton)
+TEST_DECLARE   (connect_unspecified)
 TEST_DECLARE   (ipc_listen_before_write)
 TEST_DECLARE   (ipc_listen_after_write)
 #ifndef _WIN32
@@ -468,6 +469,7 @@ TASK_LIST_START
   TEST_ENTRY  (tty_pty)
   TEST_ENTRY  (stdio_over_pipes)
   TEST_ENTRY  (ip6_pton)
+  TEST_ENTRY  (connect_unspecified)
   TEST_ENTRY  (ipc_listen_before_write)
   TEST_ENTRY  (ipc_listen_after_write)
 #ifndef _WIN32
diff --git a/uv.gyp b/uv.gyp
index fbb384a4..46606c5b 100644
--- a/uv.gyp
+++ b/uv.gyp
@@ -366,6 +366,7 @@
         'test/test-callback-order.c',
         'test/test-close-fd.c',
         'test/test-close-order.c',
+        'test/test-connect-unspecified.c',
         'test/test-connection-fail.c',
         'test/test-cwd-and-chdir.c',
         'test/test-default-loop-close.c',