--- a/netwerk/socket/nsNamedPipeIOLayer.cpp
+++ b/netwerk/socket/nsNamedPipeIOLayer.cpp
@@ -11,16 +11,17 @@
 #include "mozilla/Atomics.h"
 #include "mozilla/DebugOnly.h"
 #include "mozilla/Logging.h"
 #include "mozilla/RefPtr.h"
 #include "mozilla/Unused.h"
 #include "mozilla/net/DNS.h"
 #include "nsISupportsImpl.h"
 #include "nsNamedPipeService.h"
+#include "nsNativeCharsetUtils.h"
 #include "nsNetCID.h"
 #include "nsServiceManagerUtils.h"
 #include "nsSocketTransportService2.h"
 #include "nsString.h"
 #include "nsThreadUtils.h"
 #include "nspr.h"
 #include "private/pprio.h"
 
@@ -38,17 +39,17 @@ static PRIOMethods nsNamedPipeLayerMetho
 
 class NamedPipeInfo final : public nsINamedPipeDataObserver {
  public:
   NS_DECL_THREADSAFE_ISUPPORTS
   NS_DECL_NSINAMEDPIPEDATAOBSERVER
 
   explicit NamedPipeInfo();
 
-  nsresult Connect(const nsACString& aPath);
+  nsresult Connect(const nsAString& aPath);
   nsresult Disconnect();
 
   /**
    * Both blocking/non-blocking mode are supported in this class.
    * The default mode is non-blocking mode, however, the client may change its
    * mode to blocking mode during hand-shaking (e.g. nsSOCKSSocketInfo).
    *
    * In non-blocking mode, |Read| and |Write| should be called by clients only
@@ -227,25 +228,23 @@ NamedPipeInfo::OnError(uint32_t aError, 
       NS_NewRunnableFunction("NamedPipeInfo::OnError", [] {}),
       NS_DISPATCH_NORMAL);
 
   return NS_OK;
 }
 
 // Named pipe operations
 
-nsresult NamedPipeInfo::Connect(const nsACString& aPath) {
+nsresult NamedPipeInfo::Connect(const nsAString& aPath) {
   MOZ_ASSERT(OnSocketThread(), "not on socket thread");
 
-  HANDLE pipe;
-  nsAutoCString path(aPath);
-
-  pipe = CreateFileA(path.get(), GENERIC_READ | GENERIC_WRITE,
-                     FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr, OPEN_EXISTING,
-                     FILE_FLAG_OVERLAPPED, nullptr);
+  HANDLE pipe =
+      CreateFileW(PromiseFlatString(aPath).get(), GENERIC_READ | GENERIC_WRITE,
+                  FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr, OPEN_EXISTING,
+                  FILE_FLAG_OVERLAPPED, nullptr);
 
   if (pipe == INVALID_HANDLE_VALUE) {
     LOG_NPIO_ERROR("[%p] CreateFile error (%d)", this, GetLastError());
     return NS_ERROR_FAILURE;
   }
 
   DWORD pipeMode = PIPE_READMODE_MESSAGE;
   if (!SetNamedPipeHandleState(pipe, &pipeMode, nullptr, nullptr)) {
@@ -616,18 +615,23 @@ static PRStatus nsNamedPipeConnect(PRFil
   MOZ_ASSERT(OnSocketThread(), "not on socket thread");
 
   NamedPipeInfo* info = GetNamedPipeInfo(aFd);
   if (!info) {
     PR_SetError(PR_BAD_DESCRIPTOR_ERROR, 0);
     return PR_FAILURE;
   }
 
-  if (NS_WARN_IF(
-          NS_FAILED(info->Connect(nsDependentCString(aAddr->local.path))))) {
+  nsAutoString path;
+  if (NS_FAILED(NS_CopyNativeToUnicode(nsDependentCString(aAddr->local.path),
+                                       path))) {
+    PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
+    return PR_FAILURE;
+  }
+  if (NS_WARN_IF(NS_FAILED(info->Connect(path)))) {
     return PR_FAILURE;
   }
 
   return PR_SUCCESS;
 }
 
 static PRStatus nsNamedPipeConnectContinue(PRFileDesc* aFd, PRInt16 aOutFlags) {
   MOZ_ASSERT(OnSocketThread(), "not on socket thread");

--- a/netwerk/test/TestNamedPipeService.cpp
+++ b/netwerk/test/TestNamedPipeService.cpp
@@ -8,17 +8,17 @@
 
 #include <windows.h>
 
 #include "mozilla/Atomics.h"
 #include "mozilla/Monitor.h"
 #include "nsNamedPipeService.h"
 #include "nsNetCID.h"
 
-#define PIPE_NAME "\\\\.\\pipe\\TestNPS"
+#define PIPE_NAME L"\\\\.\\pipe\\TestNPS"
 #define TEST_STR "Hello World"
 
 using namespace mozilla;
 
 /**
  * Unlike a monitor, an event allows a thread to wait on another thread
  * completing an action without regard to ordering of the wait and the notify.
  */
@@ -178,17 +178,17 @@ nsNamedPipeDataObserver::OnError(uint32_
 }
 
 BOOL CreateAndConnectInstance(LPOVERLAPPED aOverlapped, LPHANDLE aPipe);
 BOOL ConnectToNewClient(HANDLE aPipe, LPOVERLAPPED aOverlapped);
 
 BOOL CreateAndConnectInstance(LPOVERLAPPED aOverlapped, LPHANDLE aPipe) {
   // FIXME: adjust parameters
   *aPipe =
-      CreateNamedPipeA(PIPE_NAME, PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED,
+      CreateNamedPipeW(PIPE_NAME, PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED,
                        PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT, 1,
                        65536, 65536, 3000, NULL);
 
   if (*aPipe == INVALID_HANDLE_VALUE) {
     ADD_FAILURE() << "CreateNamedPipe failed " << GetLastError();
     return FALSE;
   }
 
@@ -223,17 +223,17 @@ static nsresult CreateNamedPipe(LPHANDLE
   BOOL ret;
 
   ret = CreateAndConnectInstance(&overlapped, aServer);
   if (!ret) {
     ADD_FAILURE() << "pipe server should be pending";
     return NS_ERROR_FAILURE;
   }
 
-  *aClient = CreateFileA(PIPE_NAME, GENERIC_READ | GENERIC_WRITE,
+  *aClient = CreateFileW(PIPE_NAME, GENERIC_READ | GENERIC_WRITE,
                          FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr,
                          OPEN_EXISTING, FILE_FLAG_OVERLAPPED, nullptr);
 
   if (*aClient == INVALID_HANDLE_VALUE) {
     ADD_FAILURE() << "Unable to create pipe client";
     CloseHandle(*aServer);
     return NS_ERROR_FAILURE;
   }