diff --git a/rtc_base/signalthread.cc b/rtc_base/signalthread.cc
index 4bf7d7c4eb..48a677e378 100644
--- a/rtc_base/signalthread.cc
+++ b/rtc_base/signalthread.cc
@@ -11,6 +11,7 @@
 #include "rtc_base/signalthread.h"
 
 #include "rtc_base/checks.h"
+#include "rtc_base/ptr_util.h"
 
 namespace rtc {
 
@@ -124,6 +125,12 @@ void SignalThread::OnMessage(Message *msg) {
   }
 }
 
+SignalThread::Worker::Worker(SignalThread* parent)
+    : Thread(MakeUnique<NullSocketServer>(), /*do_init=*/false),
+      parent_(parent) {
+  DoInit();
+}
+
 SignalThread::Worker::~Worker() {
   Stop();
 }
diff --git a/rtc_base/signalthread.h b/rtc_base/signalthread.h
index 2c11da4507..8daaa0830e 100644
--- a/rtc_base/signalthread.h
+++ b/rtc_base/signalthread.h
@@ -104,9 +104,7 @@ class SignalThread
 
   class Worker : public Thread {
    public:
-    explicit Worker(SignalThread* parent)
-        : Thread(std::unique_ptr<SocketServer>(new NullSocketServer())),
-          parent_(parent) {}
+    explicit Worker(SignalThread* parent);
     ~Worker() override;
     void Run() override;
     bool IsProcessingMessages() override;
diff --git a/rtc_base/thread.cc b/rtc_base/thread.cc
index 749334125f..bb7b5919e9 100644
--- a/rtc_base/thread.cc
+++ b/rtc_base/thread.cc
@@ -124,15 +124,25 @@ Thread::ScopedDisallowBlockingCalls::~ScopedDisallowBlockingCalls() {
 // DEPRECATED.
 Thread::Thread() : Thread(SocketServer::CreateDefault()) {}
 
-Thread::Thread(SocketServer* ss) : MessageQueue(ss, false) {
-  SetName("Thread", this);  // default name
-  DoInit();
-}
+Thread::Thread(SocketServer* ss) : Thread(ss, /*do_init=*/true) {}
 
 Thread::Thread(std::unique_ptr<SocketServer> ss)
+    : Thread(std::move(ss), /*do_init=*/true) {}
+
+Thread::Thread(SocketServer* ss, bool do_init)
+    : MessageQueue(ss, /*do_init=*/false) {
+  SetName("Thread", this);  // default name
+  if (do_init) {
+    DoInit();
+  }
+}
+
+Thread::Thread(std::unique_ptr<SocketServer> ss, bool do_init)
     : MessageQueue(std::move(ss), false) {
   SetName("Thread", this);  // default name
-  DoInit();
+  if (do_init) {
+    DoInit();
+  }
 }
 
 Thread::~Thread() {
@@ -524,7 +534,9 @@ bool Thread::IsRunning() {
 #endif
 }
 
-AutoThread::AutoThread() : Thread(SocketServer::CreateDefault()) {
+AutoThread::AutoThread()
+    : Thread(SocketServer::CreateDefault(), /*do_init=*/false) {
+  DoInit();
   if (!ThreadManager::Instance()->CurrentThread()) {
     ThreadManager::Instance()->SetCurrentThread(this);
   }
@@ -539,7 +551,8 @@ AutoThread::~AutoThread() {
 }
 
 AutoSocketServerThread::AutoSocketServerThread(SocketServer* ss)
-    : Thread(ss) {
+    : Thread(ss, /*do_init=*/false) {
+  DoInit();
   old_thread_ = ThreadManager::Instance()->CurrentThread();
   // Temporarily set the current thread to nullptr so that we can keep checks
   // around that catch unintentional pointer overwrites.
diff --git a/rtc_base/thread.h b/rtc_base/thread.h
index ab6c7b1b50..568764e65b 100644
--- a/rtc_base/thread.h
+++ b/rtc_base/thread.h
@@ -111,6 +111,11 @@ class RTC_LOCKABLE Thread : public MessageQueue {
 
   explicit Thread(SocketServer* ss);
   explicit Thread(std::unique_ptr<SocketServer> ss);
+  // Constructors meant for subclasses; they should call DoInit themselves and
+  // pass false for |do_init|, so that DoInit is called only on the fully
+  // instantiated class, which avoids a vptr data race.
+  Thread(SocketServer* ss, bool do_init);
+  Thread(std::unique_ptr<SocketServer> ss, bool do_init);
 
   // NOTE: ALL SUBCLASSES OF Thread MUST CALL Stop() IN THEIR DESTRUCTORS (or
   // guarantee Stop() is explicitly called before the subclass is destroyed).