diff --git a/src/commoncode/system.py b/src/commoncode/system.py
index 605e09a..13683dd 100644
--- a/src/commoncode/system.py
+++ b/src/commoncode/system.py
@@ -30,6 +30,8 @@ def os_arch():
         os = "mac"
     elif "freebsd" in sys_platform:
         os = "freebsd"
+    elif "openbsd" in sys_platform:
+        os = "openbsd"
     elif "sunos" in sys_platform:
         os = "sunos"
     elif "haiku" in sys_platform:
@@ -49,9 +51,12 @@ def os_arch():
 on_mac = current_os == "mac"
 on_linux = current_os == "linux"
 on_freebsd = current_os == "freebsd"
+on_openbsd = current_os == "openbsd"
 on_sunos = current_os == "sunos"
 on_haiku = current_os == "haiku"
-on_posix = not on_windows and (on_mac or on_linux or on_freebsd or on_sunos or on_haiku)
+on_posix = not on_windows and (
+    on_mac or on_linux or on_freebsd or on_openbsd or on_sunos or on_haiku
+)
 
 current_os_arch = "%(current_os)s-%(current_arch)s" % locals()
 noarch = "noarch"