diff --git a/libc/proc/posix_spawn.c b/libc/proc/posix_spawn.c
index c3eaac6a942..9392ee54b30 100644
--- a/libc/proc/posix_spawn.c
+++ b/libc/proc/posix_spawn.c
@@ -350,7 +350,7 @@ static textwindows errno_t posix_spawn_nt_impl(
   // figure out flags
   uint32_t dwCreationFlags = 0;
   short flags = attrp && *attrp ? (*attrp)->flags : 0;
-  if (flags & POSIX_SPAWN_SETPGROUP)
+  if (flags & (POSIX_SPAWN_SETPGROUP | POSIX_SPAWN_SETSID))
     dwCreationFlags |= kNtCreateNewProcessGroup;
 
   // create process startinfo