diff --git a/scripts/pylib/twister/twisterlib/testplan.py b/scripts/pylib/twister/twisterlib/testplan.py
index b19cee8a1ce..22c206dfa2c 100755
--- a/scripts/pylib/twister/twisterlib/testplan.py
+++ b/scripts/pylib/twister/twisterlib/testplan.py
@@ -168,7 +168,7 @@ class TestPlan:
         sub_tests = self.options.sub_test
         if sub_tests:
             for subtest in sub_tests:
-                _subtests = self.get_testsuite(subtest)
+                _subtests = self.get_testcase(subtest)
                 for _subtest in _subtests:
                     self.run_individual_testsuite.append(_subtest.name)
 
@@ -1088,6 +1088,13 @@ class TestPlan:
 
 
     def get_testsuite(self, identifier):
+        results = []
+        for _, ts in self.testsuites.items():
+            if ts.id == identifier:
+                results.append(ts)
+        return results
+
+    def get_testcase(self, identifier):
         results = []
         for _, ts in self.testsuites.items():
             for case in ts.testcases:
diff --git a/scripts/tests/twister/test_testplan.py b/scripts/tests/twister/test_testplan.py
index b00d69ab061..0bf83ee9edb 100644
--- a/scripts/tests/twister/test_testplan.py
+++ b/scripts/tests/twister/test_testplan.py
@@ -1699,27 +1699,31 @@ def test_testplan_add_instances():
     }
 
 
-def test_testplan_get_testsuite():
+def test_testplan_get_testcase():
     testplan = TestPlan(env=mock.Mock())
     testplan.testsuites = {
-        'testsuite0': mock.Mock(testcases=[mock.Mock(), mock.Mock()]),
-        'testsuite1': mock.Mock(testcases=[mock.Mock()]),
-        'testsuite2': mock.Mock(testcases=[mock.Mock(), mock.Mock()]),
-        'testsuite3': mock.Mock(testcases=[])
+        'test1.suite0': mock.Mock(testcases=[mock.Mock(), mock.Mock()]),
+        'test1.suite1': mock.Mock(testcases=[mock.Mock(), mock.Mock()]),
+        'test1.suite2': mock.Mock(testcases=[mock.Mock(), mock.Mock()]),
+        'test1.suite3': mock.Mock(testcases=[])
     }
-    testplan.testsuites['testsuite0'].testcases[0].name = 'testcase name 0'
-    testplan.testsuites['testsuite0'].testcases[1].name = 'testcase name 1'
-    testplan.testsuites['testsuite1'].testcases[0].name = 'sample id'
-    testplan.testsuites['testsuite2'].testcases[0].name = 'dummy id'
-    testplan.testsuites['testsuite2'].testcases[1].name = 'sample id'
 
-    id = 'sample id'
+    testplan.testsuites['test1.suite0'].testcases[0].name = 'test1.suite0.case0'
+    testplan.testsuites['test1.suite0'].testcases[1].name = 'test1.suite0.case1'
+    #
+    testplan.testsuites['test1.suite1'].testcases[0].name = 'test1.suite1.case0'
+    testplan.testsuites['test1.suite1'].testcases[1].name = 'test1.suite1.case0'  # in suite duplicate
+    #
+    testplan.testsuites['test1.suite2'].testcases[0].name = 'test1.suite2.case0'
+    testplan.testsuites['test1.suite2'].testcases[1].name = 'test1.suite1.case0'  # out suite duplicate
 
-    res = testplan.get_testsuite(id)
+    id = 'test1.suite1.case0'
 
-    assert len(res) == 2
-    assert testplan.testsuites['testsuite1'] in res
-    assert testplan.testsuites['testsuite2'] in res
+    res = testplan.get_testcase(id)
+
+    assert len(res) == 3
+    assert testplan.testsuites['test1.suite1'] in res
+    assert testplan.testsuites['test1.suite2'] in res
 
 
 def test_testplan_verify_platforms_existence(caplog):