diff --git a/lldb/source/Commands/CommandObjectSettings.cpp b/lldb/source/Commands/CommandObjectSettings.cpp
--- a/lldb/source/Commands/CommandObjectSettings.cpp
+++ b/lldb/source/Commands/CommandObjectSettings.cpp
@@ -154,7 +154,7 @@
       return;
 
     // Complete option name
-    if (arg[0] != '-')
+    if (arg[0] == '-')
       return;
 
     // Complete setting value
diff --git a/lldb/test/API/functionalities/completion/TestCompletion.py b/lldb/test/API/functionalities/completion/TestCompletion.py
--- a/lldb/test/API/functionalities/completion/TestCompletion.py
+++ b/lldb/test/API/functionalities/completion/TestCompletion.py
@@ -405,6 +405,11 @@
                               ['target.process.thread.step-avoid-regexp',
                                'target.process.thread.trace-thread'])
 
+    def test_settings_set_can_complete_setting_enum_values(self):
+        """Checks that we can complete the values of an enum setting."""
+        self.complete_from_to('settings set stop-disassembly-display ',
+                              ['never', 'always', 'no-debuginfo', 'no-source'])
+
     def test_thread_plan_discard(self):
         self.build()
         (_, _, thread, _) = lldbutil.run_to_source_breakpoint(self,