diff --git a/trove_classifiers/__init__.py b/trove_classifiers/__init__.py
index c292ec2..8027cda 100644
--- a/trove_classifiers/__init__.py
+++ b/trove_classifiers/__init__.py
@@ -347,6 +347,7 @@
     "Operating System :: POSIX :: SCO",
     "Operating System :: POSIX :: SunOS/Solaris",
     "Operating System :: PalmOS",
+    "Operating System :: RISC OS",
     "Operating System :: Unix",
     "Operating System :: iOS",
     "Programming Language :: APL",