diff --git a/logprep/util/time.py b/logprep/util/time.py
index 32a209289..66046ca22 100644
--- a/logprep/util/time.py
+++ b/logprep/util/time.py
@@ -134,7 +134,11 @@ def parse_datetime(
             The parsed timestamp as datetime object.
         """
         if source_format == "UNIX":
-            parsed_datetime = int(timestamp) if len(timestamp) <= 10 else int(timestamp) / 1000
+            parsed_datetime = (
+                int(timestamp)
+                if len(timestamp) <= 10
+                else int(timestamp) / 10 ** (len(timestamp) - 10)
+            )
             parsed_datetime = cls.from_timestamp(parsed_datetime)
         elif source_format == "ISO8601":
             parsed_datetime = cls.from_string(timestamp, set_missing_utc=False)
diff --git a/tests/unit/util/test_time.py b/tests/unit/util/test_time.py
index 13e33707b..4599f6fda 100644
--- a/tests/unit/util/test_time.py
+++ b/tests/unit/util/test_time.py
@@ -168,3 +168,29 @@ def test_parse_datetime_unix_timestamp_is_always_utc(
         assert timestamp.tzinfo.tzname(timestamp) == expected_timezone_name
         for attribute, value in expected.items():
             assert getattr(timestamp, attribute) == value
+
+    @pytest.mark.parametrize(
+        "timestamp, expected_timezone_name, expected",
+        [
+            (
+                "1615634593",
+                "UTC",
+                {"year": 2021, "month": 3, "day": 13, "hour": 11, "minute": 23, "second": 13},
+            ),
+            (
+                "1615634593000",
+                "UTC",
+                {"year": 2021, "month": 3, "day": 13, "hour": 11, "minute": 23, "second": 13},
+            ),
+            (
+                "1615634593000000",
+                "UTC",
+                {"year": 2021, "month": 3, "day": 13, "hour": 11, "minute": 23, "second": 13},
+            ),
+        ],
+    )
+    def test_parse_unix_timestamp(self, timestamp, expected_timezone_name, expected):
+        parsed_timestamp = TimeParser.parse_datetime(timestamp, "UNIX", ZoneInfo("UTC"))
+        assert parsed_timestamp.tzinfo.tzname(parsed_timestamp) == expected_timezone_name
+        for attribute, value in expected.items():
+            assert getattr(parsed_timestamp, attribute) == value