diff --git a/lldb/include/lldb/Host/ProcessLaunchInfo.h b/lldb/include/lldb/Host/ProcessLaunchInfo.h
index 365d1952d173f..ab3faa69ace35 100644
--- a/lldb/include/lldb/Host/ProcessLaunchInfo.h
+++ b/lldb/include/lldb/Host/ProcessLaunchInfo.h
@@ -78,6 +78,10 @@ class ProcessLaunchInfo : public ProcessInfo {
 
   const FileAction *GetFileActionForFD(int fd) const;
 
+  /// Returns true if fd has an explicit file action, or is the destination of a
+  /// duplicate action.
+  bool IsFDRedirected(int fd) const;
+
   Flags &GetFlags() { return m_flags; }
 
   const Flags &GetFlags() const { return m_flags; }
diff --git a/lldb/source/Host/common/ProcessLaunchInfo.cpp b/lldb/source/Host/common/ProcessLaunchInfo.cpp
index 9f87e6a783adc..ce4a3bdec0dbe 100644
--- a/lldb/source/Host/common/ProcessLaunchInfo.cpp
+++ b/lldb/source/Host/common/ProcessLaunchInfo.cpp
@@ -126,6 +126,18 @@ const FileAction *ProcessLaunchInfo::GetFileActionForFD(int fd) const {
   return nullptr;
 }
 
+bool ProcessLaunchInfo::IsFDRedirected(int fd) const {
+  if (GetFileActionForFD(fd))
+    return true;
+  for (size_t i = 0; i < GetNumFileActions(); ++i) {
+    const FileAction *act = GetFileActionAtIndex(i);
+    if (act->GetAction() == FileAction::eFileActionDuplicate &&
+        act->GetActionArgument() == fd)
+      return true;
+  }
+  return false;
+}
+
 const FileSpec &ProcessLaunchInfo::GetWorkingDirectory() const {
   return m_working_dir;
 }
diff --git a/lldb/source/Host/windows/ProcessLauncherWindows.cpp b/lldb/source/Host/windows/ProcessLauncherWindows.cpp
index 50e08db749546..ec13c876eb1da 100644
--- a/lldb/source/Host/windows/ProcessLauncherWindows.cpp
+++ b/lldb/source/Host/windows/ProcessLauncherWindows.cpp
@@ -197,15 +197,19 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info,
     startupinfoex.StartupInfo.wShowWindow = SW_HIDE;
   }
 
-  DWORD flags = CREATE_NEW_CONSOLE | CREATE_UNICODE_ENVIRONMENT |
-                EXTENDED_STARTUPINFO_PRESENT;
+  DWORD flags = CREATE_UNICODE_ENVIRONMENT | EXTENDED_STARTUPINFO_PRESENT;
+  const bool stdio_redirected = launch_info.IsFDRedirected(STDIN_FILENO) &&
+                                launch_info.IsFDRedirected(STDOUT_FILENO) &&
+                                launch_info.IsFDRedirected(STDERR_FILENO);
+  if (stdio_redirected)
+    flags |= CREATE_NO_WINDOW;
+  else if (!launch_info.GetFlags().Test(eLaunchFlagDisableSTDIO) &&
+           pty_mode == PseudoConsole::Mode::None)
+    flags |= CREATE_NEW_CONSOLE;
+
   if (launch_info.GetFlags().Test(eLaunchFlagDebug))
     flags |= DEBUG_ONLY_THIS_PROCESS;
 
-  if (launch_info.GetFlags().Test(eLaunchFlagDisableSTDIO) ||
-      pty_mode != PseudoConsole::Mode::None)
-    flags &= ~CREATE_NEW_CONSOLE;
-
   std::vector<wchar_t> environment =
       CreateEnvironmentBufferW(launch_info.GetEnvironment());
 
@@ -263,19 +267,38 @@ llvm::ErrorOr<std::vector<HANDLE>> ProcessLauncherWindows::GetInheritedHandles(
     HANDLE stdout_handle, HANDLE stderr_handle, HANDLE stdin_handle) {
   std::vector<HANDLE> inherited_handles;
 
-  startupinfoex.StartupInfo.hStdError =
-      stderr_handle ? stderr_handle : GetStdHandle(STD_ERROR_HANDLE);
   startupinfoex.StartupInfo.hStdInput =
       stdin_handle ? stdin_handle : GetStdHandle(STD_INPUT_HANDLE);
   startupinfoex.StartupInfo.hStdOutput =
       stdout_handle ? stdout_handle : GetStdHandle(STD_OUTPUT_HANDLE);
 
-  if (startupinfoex.StartupInfo.hStdError)
-    inherited_handles.push_back(startupinfoex.StartupInfo.hStdError);
-  if (startupinfoex.StartupInfo.hStdInput)
-    inherited_handles.push_back(startupinfoex.StartupInfo.hStdInput);
-  if (startupinfoex.StartupInfo.hStdOutput)
-    inherited_handles.push_back(startupinfoex.StartupInfo.hStdOutput);
+  // eFileActionDuplicate stores the source fd in m_fd and the destination in
+  // m_arg. GetFileActionForFD searches by m_fd (source), so a
+  // AppendDuplicateFileAction(STDOUT, STDERR) won't be found when looking up
+  // STDERR. Scan for duplicate actions that target stderr explicitly.
+  HANDLE effective_stderr = stderr_handle;
+  if (!effective_stderr && launch_info) {
+    for (size_t i = 0; i < launch_info->GetNumFileActions(); ++i) {
+      const FileAction *act = launch_info->GetFileActionAtIndex(i);
+      if (act->GetAction() == FileAction::eFileActionDuplicate &&
+          act->GetActionArgument() == STDERR_FILENO) {
+        effective_stderr = startupinfoex.StartupInfo.hStdOutput;
+        break;
+      }
+    }
+  }
+  startupinfoex.StartupInfo.hStdError =
+      effective_stderr ? effective_stderr : GetStdHandle(STD_ERROR_HANDLE);
+
+  // PROC_THREAD_ATTRIBUTE_HANDLE_LIST requires unique entries.
+  auto push_if_new = [&](HANDLE h) {
+    if (h && std::find(inherited_handles.begin(), inherited_handles.end(), h) ==
+                 inherited_handles.end())
+      inherited_handles.push_back(h);
+  };
+  push_if_new(startupinfoex.StartupInfo.hStdError);
+  push_if_new(startupinfoex.StartupInfo.hStdInput);
+  push_if_new(startupinfoex.StartupInfo.hStdOutput);
 
   if (launch_info) {
     for (size_t i = 0; i < launch_info->GetNumFileActions(); ++i) {