diff --git a/openstackclient/shell.py b/openstackclient/shell.py
index e08eee61d..d7fe6ac19 100644
--- a/openstackclient/shell.py
+++ b/openstackclient/shell.py
@@ -76,7 +76,9 @@ class OpenStackShell(shell.OpenStackShell):
         # Loop through extensions to get API versions
         for mod in clientmanager.PLUGIN_MODULES:
             default_version = getattr(mod, 'DEFAULT_API_VERSION', None)
-            option = mod.API_VERSION_OPTION.replace('os_', '')
+            # Only replace the first instance of "os", some service names will
+            # have "os" in their name, like: "antiddos"
+            option = mod.API_VERSION_OPTION.replace('os_', '', 1)
             version_opt = str(self.cloud.config.get(option, default_version))
             if version_opt:
                 api = mod.API_NAME
diff --git a/releasenotes/notes/bug-1658614-f84a8cece6f2ef8c.yaml b/releasenotes/notes/bug-1658614-f84a8cece6f2ef8c.yaml
new file mode 100644
index 000000000..b69e384d7
--- /dev/null
+++ b/releasenotes/notes/bug-1658614-f84a8cece6f2ef8c.yaml
@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Fix wrong behavior of parsing plugin service name when the service name end
+    with keyword ``os``, like: antiddos. That cause the service api version
+    specified by users don't work.
+    [Bug `1658614 <https://bugs.launchpad.net/python-openstackclient/+bug/1658614>`_]