diff --git a/scripts/pylib/pytest-twister-harness/src/twister_harness/device/hardware_adapter.py b/scripts/pylib/pytest-twister-harness/src/twister_harness/device/hardware_adapter.py
index ef25d58cd7d..21d9c7378e4 100644
--- a/scripts/pylib/pytest-twister-harness/src/twister_harness/device/hardware_adapter.py
+++ b/scripts/pylib/pytest-twister-harness/src/twister_harness/device/hardware_adapter.py
@@ -66,8 +66,9 @@ class HardwareAdapter(DeviceAdapter):
         extra_args: list[str] = []
         runner = self.device_config.runner
         base_args.extend(['--runner', runner])
-        for param in self.device_config.runner_params:
-            extra_args.append(param)
+        if self.device_config.runner_params:
+            for param in self.device_config.runner_params:
+                extra_args.append(param)
         if board_id := self.device_config.id:
             if runner == 'pyocd':
                 extra_args.append('--board-id')
diff --git a/scripts/pylib/twister/twisterlib/harness.py b/scripts/pylib/twister/twisterlib/harness.py
index b65fa7cfada..d299c98c8e6 100644
--- a/scripts/pylib/twister/twisterlib/harness.py
+++ b/scripts/pylib/twister/twisterlib/harness.py
@@ -382,8 +382,9 @@ class Pytest(Harness):
         if runner := hardware.runner or options.west_runner:
             command.append(f'--runner={runner}')
 
-        for param in hardware.runner_params:
-            command.append(f'--runner-params={param}')
+        if hardware.runner_params:
+            for param in hardware.runner_params:
+                command.append(f'--runner-params={param}')
 
         if options.west_flash and options.west_flash != []:
             command.append(f'--west-flash-extra-args={options.west_flash}')