diff --git a/util/sys_info.cc b/util/sys_info.cc
index a1ce3e9..5fefc9b 100644
--- a/util/sys_info.cc
+++ b/util/sys_info.cc
@@ -72,9 +72,7 @@
 
   return static_cast<int>(res);
 #elif defined(OS_WIN)
-  SYSTEM_INFO system_info = {};
-  ::GetNativeSystemInfo(&system_info);
-  return system_info.dwNumberOfProcessors;
+  return ::GetActiveProcessorCount(ALL_PROCESSOR_GROUPS);
 #else
 #error
 #endif
diff --git a/util/worker_pool.cc b/util/worker_pool.cc
index 92fadd4..60bcfbf 100644
--- a/util/worker_pool.cc
+++ b/util/worker_pool.cc
@@ -7,10 +7,50 @@
 #include "base/command_line.h"
 #include "base/strings/string_number_conversions.h"
 #include "tools/gn/switches.h"
+#include "util/build_config.h"
 #include "util/sys_info.h"
 
+#if defined(OS_WIN)
+#include <windows.h>
+#endif
+
 namespace {
 
+#if defined(OS_WIN)
+class ProcessorGroupSetter {
+ public:
+  void SetProcessorGroup(std::thread* thread);
+
+ private:
+  int group_ = 0;
+  GROUP_AFFINITY group_affinity_;
+  int num_available_cores_in_group_ = ::GetActiveProcessorCount(group_) / 2;
+  const int num_groups_ = ::GetActiveProcessorGroupCount();
+};
+
+void ProcessorGroupSetter::SetProcessorGroup(std::thread* thread) {
+  if (num_groups_ <= 1)
+    return;
+
+  const HANDLE thread_handle = thread->native_handle();
+  ::GetThreadGroupAffinity(thread_handle, &group_affinity_);
+  group_affinity_.Group = group_;
+  const bool success =
+      ::SetThreadGroupAffinity(thread_handle, &group_affinity_, nullptr);
+  DCHECK(success);
+
+  // Move to next group once one thread has been assigned per core in |group_|.
+  num_available_cores_in_group_--;
+  if (num_available_cores_in_group_ <= 0) {
+    group_++;
+    if (group_ >= num_groups_) {
+      group_ = 0;
+    }
+    num_available_cores_in_group_ = ::GetActiveProcessorCount(group_) / 2;
+  }
+}
+#endif
+
 int GetThreadCount() {
   std::string thread_count =
       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
@@ -46,9 +86,22 @@
 WorkerPool::WorkerPool() : WorkerPool(GetThreadCount()) {}
 
 WorkerPool::WorkerPool(size_t thread_count) : should_stop_processing_(false) {
+#if defined(OS_WIN)
+  ProcessorGroupSetter processor_group_setter;
+#endif
+
   threads_.reserve(thread_count);
-  for (size_t i = 0; i < thread_count; ++i)
+  for (size_t i = 0; i < thread_count; ++i) {
     threads_.emplace_back([this]() { Worker(); });
+
+#if defined(OS_WIN)
+    // Set thread processor group. This is needed for systems with more than 64
+    // logical processors, wherein available processors are divided into groups,
+    // and applications that need to use more than one group's processors must
+    // manually assign their threads to groups.
+    processor_group_setter.SetProcessorGroup(&threads_.back());
+#endif
+  }
 }
 
 WorkerPool::~WorkerPool() {