diff --git a/include/jemalloc/internal/jemalloc_internal_decls.h b/include/jemalloc/internal/jemalloc_internal_decls.h
index 983027c8..77ba1c9a 100644
--- a/include/jemalloc/internal/jemalloc_internal_decls.h
+++ b/include/jemalloc/internal/jemalloc_internal_decls.h
@@ -32,7 +32,7 @@
 #    include <sys/uio.h>
 #  endif
 #  include <pthread.h>
-#  if defined(__FreeBSD__) || defined(__DragonFly__)
+#  if defined(__FreeBSD__) || defined(__DragonFly__) || defined(__OpenBSD__)
 #  include <pthread_np.h>
 #  include <sched.h>
 #  if defined(__FreeBSD__)
diff --git a/include/jemalloc/jemalloc_macros.h.in b/include/jemalloc/jemalloc_macros.h.in
index ebb3137e..2de3f27d 100644
--- a/include/jemalloc/jemalloc_macros.h.in
+++ b/include/jemalloc/jemalloc_macros.h.in
@@ -142,7 +142,7 @@
 #  define JEMALLOC_COLD
 #endif
 
-#if (defined(__APPLE__) || defined(__FreeBSD__)) && !defined(JEMALLOC_NO_RENAME)
+#if (defined(__APPLE__) || defined(__FreeBSD__) || defined(__OpenBSD__)) && !defined(JEMALLOC_NO_RENAME)
 #  define JEMALLOC_SYS_NOTHROW
 #else
 #  define JEMALLOC_SYS_NOTHROW JEMALLOC_NOTHROW
diff --git a/src/background_thread.c b/src/background_thread.c
index 3bb8d26c..f22174d6 100644
--- a/src/background_thread.c
+++ b/src/background_thread.c
@@ -80,6 +80,9 @@ background_thread_info_init(tsdn_t *tsdn, background_thread_info_t *info) {
 
 static inline bool
 set_current_thread_affinity(int cpu) {
+#ifdef __OpenBSD__
+	return false;
+#else
 #if defined(JEMALLOC_HAVE_SCHED_SETAFFINITY)
 	cpu_set_t cpuset;
 #else
@@ -110,6 +113,7 @@ set_current_thread_affinity(int cpu) {
 #  endif
 	return ret != 0;
 #endif
+#endif
 }
 
 #define BILLION UINT64_C(1000000000)