diff --git a/tests/test_utils.py b/tests/test_utils.py
index 57d58cf9e..88a07219d 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -17,6 +17,7 @@
 
 import pytest
 
+import numpy as np
 
 def test_format_byte_size():
     assert format_byte_size(byte_size=12345) == "12.35KB"
@@ -145,6 +146,7 @@ def test_calculate_number_of_cpu_negative_value(self):
 def test_is_ascending_series():
     assert is_ascending_series(series=[1, 1, 1])
     assert is_ascending_series(series=[1, 2, 3])
+    assert is_ascending_series(series=[1, np.nan, 3])
     assert not is_ascending_series(series=[1, 2, 1])
 
 
diff --git a/tests/unit_tests/test_time_series.py b/tests/unit_tests/test_time_series.py
index 88e831603..b47a0336f 100644
--- a/tests/unit_tests/test_time_series.py
+++ b/tests/unit_tests/test_time_series.py
@@ -12,6 +12,7 @@
     check_data_orientation,
     check_timestamps_match_first_dimension,
     check_timestamps_ascending,
+    check_timestamps_with_nans,
     check_missing_unit,
     check_resolution,
     check_timestamp_of_the_first_sample_is_not_negative,
@@ -226,6 +227,9 @@ def test_pass_check_timestamps_ascending_pass():
     time_series = pynwb.TimeSeries(name="test_time_series", unit="test_units", data=[1, 2, 3], timestamps=[1, 2, 3])
     assert check_timestamps_ascending(time_series) is None
 
+def test_pass_check_timestamps_ascending_with_nans_pass():
+    time_series = pynwb.TimeSeries(name="test_time_series", unit="test_units", data=[1, 2, 3], timestamps=[1, np.nan, 3])
+    assert check_timestamps_ascending(time_series) is None
 
 def test_check_timestamps_ascending_fail():
     time_series = pynwb.TimeSeries(name="test_time_series", unit="test_units", data=[1, 2, 3], timestamps=[1, 3, 2])
@@ -238,6 +242,31 @@ def test_check_timestamps_ascending_fail():
         location="/",
     )
 
+def test_check_timestamps_ascending_with_nans_fail():
+    time_series = pynwb.TimeSeries(name="test_time_series", unit="test_units", data=[1, 2, 3], timestamps=[np.nan, 3, 2])
+    assert check_timestamps_ascending(time_series) == InspectorMessage(
+        message="test_time_series timestamps are not ascending.",
+        importance=Importance.BEST_PRACTICE_VIOLATION,
+        check_function_name="check_timestamps_ascending",
+        object_type="TimeSeries",
+        object_name="test_time_series",
+        location="/",
+    )
+
+def test_check_timestamps_with_nans_pass():
+    time_series = pynwb.TimeSeries(name="test_time_series", unit="test_units", data=[1, 2, 3], timestamps=[1, 2, 3])
+    assert check_timestamps_with_nans(time_series) is None
+
+def test_check_timestamps_with_nans_fail():
+    time_series = pynwb.TimeSeries(name="test_time_series", unit="test_units", data=[1, 2, 3], timestamps=[np.nan, 2, 3])
+    assert check_timestamps_with_nans(time_series) == InspectorMessage(
+        message="test_time_series timestamps contain NaN values.",
+        importance=Importance.BEST_PRACTICE_VIOLATION,
+        check_function_name="check_timestamps_with_nans",
+        object_type="TimeSeries",
+        object_name="test_time_series",
+        location="/",
+    )
 
 def test_check_timestamp_of_the_first_sample_is_not_negative_with_timestamps_fail():
     time_series = pynwb.TimeSeries(name="test_time_series", unit="test_units", data=[1, 2, 3], timestamps=[-1, 0, 1])