diff --git a/rteval-cmd b/rteval-cmd
index 1e6a7fc86baa..70996acce626 100755
--- a/rteval-cmd
+++ b/rteval-cmd
@@ -40,7 +40,7 @@ import os
 import time
 import re
 import shutil
-import optparse
+import argparse
 import tempfile
 import requests
 import lxml.etree
@@ -115,66 +115,84 @@ def parse_options(cfg, parser, cmdargs):
     # thus they are prefixed with 'rteval___'.
     # See rteval/rtevalConfig::UpdateFromOptionParser() method for more info
     #
-    parser.add_option("-d", "--duration", dest="rteval___duration",
-                      type="string", default=rtevcfg.duration, metavar="DURATION",
-                      help="specify length of test run (default: %default)")
-    parser.add_option("-v", "--verbose", dest="rteval___verbose",
+    parser.add_argument("-d", "--duration", dest="rteval___duration",
+                      type=str, default=rtevcfg.duration, metavar="DURATION",
+                      help=f"specify length of test run (default: {rtevcfg.duration})")
+    parser.add_argument("-v", "--verbose", dest="rteval___verbose",
                       action="store_true", default=rtevcfg.verbose,
-                      help="turn on verbose prints (default: %default)")
-    parser.add_option("-q", "--quiet", dest="rteval___quiet",
+                      help=f"turn on verbose prints (default: {rtevcfg.verbose})")
+    parser.add_argument("-q", "--quiet", dest="rteval___quiet",
                       action="store_true", default=rtevcfg.quiet,
-                      help="turn on quiet mode (default: %default)")
-    parser.add_option("-w", "--workdir", dest="rteval___workdir",
-                      type="string", default=rtevcfg.workdir, metavar="DIRECTORY",
-                      help="top directory for rteval data (default: %default)")
-    parser.add_option("-l", "--loaddir", dest="rteval___srcdir",
-                      type="string", default=rtevcfg.srcdir, metavar="DIRECTORY",
-                      help="directory for load source tarballs (default: %default)")
-    parser.add_option("-i", "--installdir", dest="rteval___installdir",
-                      type="string", default=rtevcfg.installdir, metavar="DIRECTORY",
-                      help="place to locate installed templates (default: %default)")
-    parser.add_option("-s", "--sysreport", dest="rteval___sysreport",
+                      help=f"turn on quiet mode (default: {rtevcfg.quiet})")
+    parser.add_argument("-w", "--workdir", dest="rteval___workdir",
+                      type=str, default=rtevcfg.workdir, metavar="DIRECTORY",
+                      help=f"top directory for rteval data (default: {rtevcfg.workdir})")
+    parser.add_argument("-l", "--loaddir", dest="rteval___srcdir",
+                      type=str, default=rtevcfg.srcdir, metavar="DIRECTORY",
+                      help=f"directory for load source tarballs (default: {rtevcfg.srcdir})")
+    parser.add_argument("-i", "--installdir", dest="rteval___installdir",
+                      type=str, default=rtevcfg.installdir, metavar="DIRECTORY",
+                      help=f"place to locate installed templates (default: {rtevcfg.installdir})")
+    parser.add_argument("-s", "--sysreport", dest="rteval___sysreport",
                       action="store_true", default=rtevcfg.sysreport,
-                      help='run sysreport to collect system data (default: %default)')
-    parser.add_option("-D", '--debug', dest='rteval___debugging',
+                      help=f'run sysreport to collect system data (default: {rtevcfg.sysreport})')
+    parser.add_argument("-D", '--debug', dest='rteval___debugging',
                       action='store_true', default=rtevcfg.debugging,
-                      help='turn on debug prints (default: %default)')
+                      help=f'turn on debug prints (default: {rtevcfg.debugging})')
     #parser.add_option("-X", '--xmlrpc-submit', dest='rteval___xmlrpc',
     #                  action='store', default=rtevcfg.xmlrpc, metavar='HOST',
     #                  help='Hostname to XML-RPC server to submit reports')
     #parser.add_option("-P", "--xmlrpc-no-abort", dest="rteval___xmlrpc_noabort",
     #                  action='store_true', default=False,
     #                  help="Do not abort if XML-RPC server do not respond to ping request");
-    parser.add_option("-Z", '--summarize', dest='rteval___summarize',
+    parser.add_argument("-Z", '--summarize', dest='rteval___summarize',
                       action='store_true', default=False,
                       help='summarize an already existing XML report')
-    parser.add_option("-H", '--raw-histogram', dest='rteval___rawhistogram',
+    parser.add_argument("-H", '--raw-histogram', dest='rteval___rawhistogram',
                       action='store_true', default=False,
                       help='Generate raw histogram data for an already existing XML report')
-    parser.add_option("-f", "--inifile", dest="rteval___inifile",
-                      type='string', default=None, metavar="FILE",
+    parser.add_argument("-f", "--inifile", dest="rteval___inifile",
+                      type=str, default=None, metavar="FILE",
                       help="initialization file for configuring loads and behavior")
-    parser.add_option("-a", "--annotate", dest="rteval___annotate",
-                      type="string", default=None, metavar="STRING",
+    parser.add_argument("-a", "--annotate", dest="rteval___annotate",
+                      type=str, default=None, metavar="STRING",
                       help="Add a little annotation which is stored in the report")
-    parser.add_option("-L", "--logging", dest="rteval___logging",
+    parser.add_argument("-L", "--logging", dest="rteval___logging",
                       action='store_true', default=False,
                       help='log the output of the loads in the report directory')
-    parser.add_option("-O", "--onlyload", dest="rteval___onlyload",
+    parser.add_argument("-O", "--onlyload", dest="rteval___onlyload",
                       action='store_true', default=False,
                       help="only run the loads (don't run measurement threads)")
-    parser.add_option("-V", "--version", dest="rteval___version",
+    parser.add_argument("-V", "--version", dest="rteval___version",
                       action='store_true', default=False,
                       help='print rteval version and exit')
-    parser.add_option("-S", "--source-download", dest="rteval___srcdownload",
-                        type="string", default=None, metavar="KERNEL_VERSION",
+    parser.add_argument("-S", "--source-download", dest="rteval___srcdownload",
+                        type=str, default=None, metavar="KERNEL_VERSION",
                         help='download a source kernel from kernel.org and exit')
 
 
     if not cmdargs:
         cmdargs = ["--help"]
 
-    (cmd_opts, cmd_args) = parser.parse_args(args=cmdargs)
+    # if -Z/--summarize is specified, add the files to be summarized to cmd_args, and add -Z to cmd_opts
+    cmd_args = []
+    if (sys.argv.count('-Z')+sys.argv.count('--summarize')) > 0:
+        try:
+            ind = cmdargs.index('-Z')
+        except ValueError:
+            ind = cmdargs.index('--summarize')
+        cmd_args = cmdargs[ind+1:]
+        cmdargs = cmdargs[:ind+1]
+    # if -H/--raw-histogram is specified, add the files to be summarized to cmd_args, and add -Z to cmd_opts
+    elif (sys.argv.count('-H')+sys.argv.count('--raw-histogram')) > 0:
+        try:
+            ind = cmdargs.index('-H')
+        except ValueError:
+            ind = cmdargs.index('--raw-histogram')
+        cmd_args = cmdargs[ind+1:]
+        cmdargs = cmdargs[:ind+1]
+    cmd_opts = parser.parse_args(args=cmdargs)
+
     if cmd_opts.rteval___version:
         print(f"rteval version {RTEVAL_VERSION}")
         sys.exit(0)
@@ -196,7 +214,7 @@ def parse_options(cfg, parser, cmdargs):
         cmd_opts.rteval___duration = float(v) * mult
 
     # Update the config object with the parsed arguments
-    cfg.UpdateFromOptionParser(parser)
+    cfg.UpdateFromOptionParser(cmd_opts)
 
     return cmd_args
 
@@ -266,7 +284,7 @@ if __name__ == '__main__':
         measuremods = MeasurementModules(config, logger=logger)
 
         # parse command line options
-        parser = optparse.OptionParser()
+        parser = argparse.ArgumentParser()
         loadmods.SetupModuleOptions(parser)
         measuremods.SetupModuleOptions(parser)
         cmd_args = parse_options(config, parser, sys.argv[1:])
diff --git a/rteval/modules/__init__.py b/rteval/modules/__init__.py
index d52dd597186a..253e72abf8aa 100644
--- a/rteval/modules/__init__.py
+++ b/rteval/modules/__init__.py
@@ -25,7 +25,7 @@
 import time
 from datetime import datetime
 import threading
-import optparse
+import argparse
 import libxml2
 from rteval.Log import Log
 from rteval.rtevalConfig import rtevalCfgSection
@@ -294,12 +294,11 @@ the information provided by the module"""
     def SetupModuleOptions(self, parser, config):
         """Sets up a separate optptarse OptionGroup per module with its supported parameters"""
 
-        grparser = optparse.OptionGroup(parser, "Group Options for %s modules" % self.__modtype)
-        grparser.add_option('--%s-cpulist' % self.__modtype,
+        grparser = parser.add_argument_group("Group Options for %s modules" % self.__modtype)
+        grparser.add_argument('--%s-cpulist' % self.__modtype,
                             dest='%s___cpulist' % self.__modtype, action='store', default="",
                             help='CPU list where %s modules will run' % self.__modtype,
                             metavar='LIST')
-        parser.add_option_group(grparser)
 
         for (modname, mod) in list(self.__modsloaded.items()):
             opts = mod.ModuleParameters()
@@ -313,7 +312,7 @@ the information provided by the module"""
                 # Ignore if a section is not found
                 cfg = None
 
-            grparser = optparse.OptionGroup(parser, "Options for the %s module" % shortmod)
+            grparser = parser.add_argument_group("Options for the %s module" % shortmod)
             for (o, s) in list(opts.items()):
                 descr = 'descr' in s and s['descr'] or ""
                 metavar = 'metavar' in s and s['metavar'] or None
@@ -328,14 +327,13 @@ the information provided by the module"""
                     default = 'default' in s and s['default'] or None
 
 
-                grparser.add_option('--%s-%s' % (shortmod, o),
+                grparser.add_argument('--%s-%s' % (shortmod, o),
                                     dest="%s___%s" % (shortmod, o),
                                     action='store',
                                     help='%s%s' % (descr,
                                                    default and ' (default: %s)' % default or ''),
                                     default=default,
                                     metavar=metavar)
-            parser.add_option_group(grparser)
 
 
     def InstantiateModule(self, modname, modcfg, modroot=None):
diff --git a/rteval/rtevalConfig.py b/rteval/rtevalConfig.py
index 41f1a567720f..ec14a13adcd9 100644
--- a/rteval/rtevalConfig.py
+++ b/rteval/rtevalConfig.py
@@ -286,11 +286,11 @@ class rtevalConfig:
         return self.__config_files.__contains__(fname)
 
 
-    def UpdateFromOptionParser(self, parser):
+    def UpdateFromOptionParser(self, cmd_opts):
         "Parse through the command line options and update the appropriate config settings"
 
         last_sect = None
-        for sk, v in sorted(vars(parser.values).items()):
+        for sk, v in sorted(vars(cmd_opts).items()):
             # optparse key template: {sectionname}___{key}
             k = sk.split('___')
             if k[0] != last_sect:
diff --git a/server/rteval_testserver.py b/server/rteval_testserver.py
index 3f0c3c73733c..6cac85bcfe52 100644
--- a/server/rteval_testserver.py
+++ b/server/rteval_testserver.py
@@ -31,6 +31,7 @@ import signal
 from xmlrpc.server import SimpleXMLRPCServer
 from xmlrpc.server import SimpleXMLRPCRequestHandler
 from optparse import OptionParser
+import argparse
 
 import xmlrpc_API1
 from Logger import Logger
@@ -110,16 +111,16 @@ rtevalserver = None
 #
 
 if __name__ == '__main__':
-    parser = OptionParser(version="%prog v0.1")
+    parser = argparse.ArgumentParser(version="%prog v0.1")
 
-    parser.add_option("-L", "--listen", action="store", dest="listen", default=LISTEN,
+    parser.add_argument("-L", "--listen", action="store", dest="listen", default=LISTEN,
                       help="Which interface to listen to [default: %default]", metavar="IPADDR")
-    parser.add_option("-P", "--port", action="store", type="int", dest="port", default=PORT,
+    parser.add_argument("-P", "--port", action="store", type="int", dest="port", default=PORT,
                       help="Which port to listen to [default: %default]",  metavar="PORT")
-    parser.add_option("-l", "--log", action="store", dest="logfile", default=None,
+    parser.add_argument("-l", "--log", action="store", dest="logfile", default=None,
                       help="Where to log requests.", metavar="FILE")
 
-    (options, args) = parser.parse_args()
+    options = parser.parse_args()
 
     logger = Logger(options.logfile, "RTeval")
     rtevalserver = RTevald(options, logger)
diff --git a/server/unittest.py b/server/unittest.py
index 4d53f46590ce..7dcdef08c098 100644
--- a/server/unittest.py
+++ b/server/unittest.py
@@ -1,5 +1,5 @@
 import sys, threading, time, signal, libxml2
-from optparse import OptionParser
+import argparse
 from rteval_testserver import RTevald
 from Logger import Logger
 
@@ -14,10 +14,10 @@ class ServerThread(threading.Thread):
         self.port = port
         self.log = Logger('unit-test-server.log','rteval-xmlrpc-testsrv')
 
-        parser = OptionParser()
-        parser.add_option("-L", "--listen", action="store", dest="listen", default="127.0.0.1",
+        parser = argparse.ArgumentParser()
+        parser.add_argument("-L", "--listen", action="store", dest="listen", default="127.0.0.1",
                           help="Which interface to listen to [default: %default]", metavar="IPADDR")
-        parser.add_option("-P", "--port", action="store", type="int", dest="port", default=self.port,
+        parser.add_argument("-P", "--port", action="store", type="int", dest="port", default=self.port,
                           help="Which port to listen to [default: %default]",  metavar="PORT")
 
         (options, args) = parser.parse_args()
