diff --git a/cmake/scripts/argparse2help.py b/cmake/scripts/argparse2help.py
index b406b3cbdf4cd..d7032bd34f67f 100644
--- a/cmake/scripts/argparse2help.py
+++ b/cmake/scripts/argparse2help.py
@@ -18,6 +18,9 @@ def write_header(parser, fileName):
 	splitPath = sys.argv[2].split("/")
 	file.write("#ifndef ROOT_{}\n".format(splitPath[len(splitPath)-1].partition(".")[0]))
 	file.write("#define ROOT_{}\n".format(splitPath[len(splitPath)-1].partition(".")[0]))
+	file.write("constexpr static const char kCommandLineShortHelp[] = R\"RAW(\n")
+	file.write(parser.format_usage() + "\n")
+	file.write(")RAW\";\n\n")
 	file.write("constexpr static const char kCommandLineOptionsHelp[] = R\"RAW(\n")
 	file.write(parser.format_usage() + "\n")
 	if parser.description is not None:
diff --git a/main/src/hadd.cxx b/main/src/hadd.cxx
index 1b6c904ef2dad..d27ebd1efe0cc 100644
--- a/main/src/hadd.cxx
+++ b/main/src/hadd.cxx
@@ -230,6 +230,7 @@ struct HAddArgs {
    bool fDebug;
    bool fKeepCompressionAsIs;
    bool fUseFirstInputCompression;
+   bool fHelp;
 
    std::optional<std::string> fWorkingDir;
    std::optional<IntFlag_t> fNProcesses;
@@ -565,6 +566,10 @@ static std::optional<HAddArgs> ParseArgs(int argc, char **argv)
          PARSE_FLAG(FlagToggle, arg, "k", args.fSkipErrors);
          PARSE_FLAG(FlagToggle, arg, "O", args.fReoptimize);
          PARSE_FLAG(FlagToggle, arg, "dbg", args.fDebug);
+         // Accept --help, -help and -h as "help"
+         PARSE_FLAG(FlagToggle, arg, "-help", args.fHelp);
+         PARSE_FLAG(FlagToggle, arg, "help", args.fHelp);
+         PARSE_FLAG(FlagToggle, arg, "h", args.fHelp);
          PARSE_FLAG(FlagArg, argc, argv, argIdx, "d", args.fWorkingDir);
          PARSE_FLAG(FlagArg, argc, argv, argIdx, "j", args.fNProcesses, {0});
          PARSE_FLAG(FlagArg, argc, argv, argIdx, "Ltype", args.fObjectFilterType, {}, ConvertFilterType);
@@ -653,16 +658,16 @@ static Int_t ParseFilterFile(const std::optional<std::string> &filterFileName,
 
 int main(int argc, char **argv)
 {
-   if (argc < 3 || "-h" == std::string(argv[1]) || "--help" == std::string(argv[1])) {
-      fprintf(stderr, kCommandLineOptionsHelp);
-      return (argc == 2 && ("-h" == std::string(argv[1]) || "--help" == std::string(argv[1]))) ? 0 : 1;
-   }
-
    const auto argsOpt = ParseArgs(argc, argv);
    if (!argsOpt)
       return 1;
    const HAddArgs &args = *argsOpt;
 
+   if (args.fHelp) {
+      fputs(kCommandLineOptionsHelp, stderr);
+      return 0;
+   }
+
    ROOT::TIOFeatures features = args.fFeatures.value_or(ROOT::TIOFeatures{});
    Int_t maxopenedfiles = args.fMaxOpenedFiles.value_or(0);
    gHaddVerbosity = args.fVerbosity.value_or(kDefaultHaddVerbosity);
@@ -705,10 +710,12 @@ int main(int argc, char **argv)
    const char *targetname = 0;
    if (!args.fOutputArgIdx) {
       Err() << "missing output file.\n";
+      fputs(kCommandLineShortHelp, stderr);
       return 1;
    }
    if (!args.fFirstInputIdx) {
       Err() << "missing input file.\n";
+      fputs(kCommandLineShortHelp, stderr);
       return 1;
    }
    targetname = argv[args.fOutputArgIdx];
diff --git a/roottest/root/io/hadd/CMakeLists.txt b/roottest/root/io/hadd/CMakeLists.txt
index d1c78b1d10604..ec676439d2256 100644
--- a/roottest/root/io/hadd/CMakeLists.txt
+++ b/roottest/root/io/hadd/CMakeLists.txt
@@ -77,6 +77,16 @@ ROOTTEST_ADD_TEST(test_MergeFilterWhitelist
 ################################################################
 #                 argument parsing tests                       #
 ################################################################
+ROOTTEST_ADD_TEST(test_hadd_args_missing_output
+                  COMMAND ${ROOT_hadd_CMD}
+                  PASSREGEX "Error in <hadd>: missing output file."
+)
+
+ROOTTEST_ADD_TEST(test_hadd_args_missing_input
+                  COMMAND ${ROOT_hadd_CMD} foo.root
+                  PASSREGEX "Error in <hadd>: missing input file."
+)
+
 ROOTTEST_ADD_TEST(test_hadd_args_gen_input
                   COPY_TO_BUILDDIR hadd_gen_input_tree.C hadd_args_verify.C
                   PRECMD ${CMAKE_COMMAND} -E rm -f hadd_args_in.root
@@ -84,6 +94,24 @@ ROOTTEST_ADD_TEST(test_hadd_args_gen_input
                   FIXTURES_SETUP root-io-hadd-test_hadd_args_gen_input-fixture
 )
 
+ROOTTEST_ADD_TEST(test_hadd_args_help_short
+                  FIXTURES_REQUIRED root-io-hadd-test_hadd_args_gen_input-fixture
+                  COMMAND ${ROOT_hadd_CMD} -n0 hadd_args_n0_out.root hadd_args_in.root -h
+                  PASSREGEX "usage: hadd"
+)
+
+ROOTTEST_ADD_TEST(test_hadd_args_help_long
+                  FIXTURES_REQUIRED root-io-hadd-test_hadd_args_gen_input-fixture
+                  COMMAND ${ROOT_hadd_CMD} -n0 hadd_args_n0_out.root hadd_args_in.root -help
+                  PASSREGEX "usage: hadd"
+)
+
+ROOTTEST_ADD_TEST(test_hadd_args_help_long2
+                  FIXTURES_REQUIRED root-io-hadd-test_hadd_args_gen_input-fixture
+                  COMMAND ${ROOT_hadd_CMD} -n0 hadd_args_n0_out.root hadd_args_in.root --help
+                  PASSREGEX "usage: hadd"
+)
+
 ROOTTEST_ADD_TEST(test_hadd_args_n0
                   FIXTURES_REQUIRED root-io-hadd-test_hadd_args_gen_input-fixture
                   PRECMD ${CMAKE_COMMAND} -E rm -f hadd_args_n0_out.root