diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 8203aded7d5..ccb46a6337b 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -660,8 +660,9 @@ def _use_posix_spawn():
         # os.posix_spawn() is not available
         return False
 
-    if sys.platform == 'darwin':
-        # posix_spawn() is a syscall on macOS and properly reports errors
+    if sys.platform in ('darwin', 'sunos5'):
+        # posix_spawn() is a syscall on both macOS and Solaris,
+        # and properly reports errors
         return True
 
     # Check libc name and runtime libc version
diff --git a/Misc/NEWS.d/next/Library/2021-08-17-16-01-44.bpo-44935.roUl0G.rst b/Misc/NEWS.d/next/Library/2021-08-17-16-01-44.bpo-44935.roUl0G.rst
new file mode 100644
index 00000000000..3d41c3be140
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-08-17-16-01-44.bpo-44935.roUl0G.rst
@@ -0,0 +1,2 @@
+:mod:`subprocess` on Solaris now also uses :func:`os.posix_spawn()` for
+better performance.