diff --git a/src/dwarfs/worker_group.cpp b/src/dwarfs/worker_group.cpp
index 7a8401f7..8fada2db 100644
--- a/src/dwarfs/worker_group.cpp
+++ b/src/dwarfs/worker_group.cpp
@@ -33,6 +33,7 @@
 
 #include <folly/Conv.h>
 #include <folly/portability/PThread.h>
+#include <folly/portability/Windows.h>
 #include <folly/system/ThreadName.h>
 
 #include "dwarfs/error.h"
@@ -109,11 +110,11 @@ class basic_worker_group final : public worker_group::impl, private Policy {
     }
 
     for (size_t i = 0; i < num_workers; ++i) {
-      workers_.emplace_back([this, /*niceness,*/ group_name, i] {
+      workers_.emplace_back([this, niceness, group_name, i] {
         folly::setThreadName(folly::to<std::string>(group_name, i + 1));
         // TODO: FIXME: this is broken
         // [[maybe_unused]] auto rv = ::nice(niceness);
-        do_work();
+        do_work(niceness > 0);
       });
     }
   }
@@ -220,7 +221,10 @@ class basic_worker_group final : public worker_group::impl, private Policy {
  private:
   using jobs_t = std::queue<worker_group::job_t>;
 
-  void do_work() {
+  void do_work(bool is_background [[maybe_unused]]) {
+#ifdef _WIN32
+    auto hthr = ::GetCurrentThread();
+#endif
     for (;;) {
       worker_group::job_t job;
 
@@ -246,7 +250,17 @@ class basic_worker_group final : public worker_group::impl, private Policy {
 
       {
         typename Policy::task task(this);
+#ifdef _WIN32
+        if (is_background) {
+          ::SetThreadPriority(hthr, THREAD_MODE_BACKGROUND_BEGIN);
+        }
+#endif
         job();
+#ifdef _WIN32
+        if (is_background) {
+          ::SetThreadPriority(hthr, THREAD_MODE_BACKGROUND_END);
+        }
+#endif
       }
 
       {