diff --git a/sop-java-picocli/src/main/kotlin/sop/cli/picocli/SOPExceptionExitCodeMapper.kt b/sop-java-picocli/src/main/kotlin/sop/cli/picocli/SOPExceptionExitCodeMapper.kt
index 29aa77b..5778bb9 100644
--- a/sop-java-picocli/src/main/kotlin/sop/cli/picocli/SOPExceptionExitCodeMapper.kt
+++ b/sop-java-picocli/src/main/kotlin/sop/cli/picocli/SOPExceptionExitCodeMapper.kt
@@ -21,6 +21,8 @@ class SOPExceptionExitCodeMapper : IExitCodeExceptionMapper {
                 // Unmatched subcommand
                 SOPGPException.UnsupportedSubcommand.EXIT_CODE
             }
+        } else if (exception is MissingParameterException) {
+            SOPGPException.MissingArg.EXIT_CODE
         } else if (exception is ParameterException) {
             // Invalid option (e.g. `--as invalid`)
             SOPGPException.UnsupportedOption.EXIT_CODE