diff --git a/CHANGELOG.md b/CHANGELOG.md
index 93eda9e3a..224c342fd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@
 
 ### Fixes
 
+- Use `wday=0` for Mondays in `tick_calendar` (like `calendar_day_of_week`).
+
 ## 0.1.5
 
 ### Features
diff --git a/temporian/core/operators/test/test_tick_calendar.py b/temporian/core/operators/test/test_tick_calendar.py
index 59c43f6b7..00f847c51 100644
--- a/temporian/core/operators/test/test_tick_calendar.py
+++ b/temporian/core/operators/test/test_tick_calendar.py
@@ -145,7 +145,7 @@ def test_weekdays(self):
             timestamps=timestamps,
         )
 
-        result = evset.tick_calendar(hour="*", wday=6)
+        result = evset.tick_calendar(hour="*", wday=5)
         assertOperatorResult(self, result, expected_evset, check_sampling=False)
 
 
diff --git a/temporian/implementation/numpy/operators/tick_calendar.py b/temporian/implementation/numpy/operators/tick_calendar.py
index 7e46500fd..b7ef5cddd 100644
--- a/temporian/implementation/numpy/operators/tick_calendar.py
+++ b/temporian/implementation/numpy/operators/tick_calendar.py
@@ -31,6 +31,14 @@ def __init__(self, operator: TickCalendar) -> None:
         assert isinstance(operator, TickCalendar)
         super().__init__(operator)
 
+    def _wday_py_to_cpp(self, py_wday: int) -> int:
+        """Converts wday number from Python (wday=0 for Monday) to C++
+        convention (wday=0 for Sunday).
+        This is required to keep coherency between calendar_day_of_week()
+        operator (which uses datetime.weekday()) and tick_calendar() (which
+        uses tm_wday in tick_calendar.cc)."""
+        return (py_wday + 1) % 7
+
     def _get_arg_range(
         self,
         arg_value: Union[int, Literal["*"]],
@@ -66,9 +74,12 @@ def __call__(self, input: EventSet) -> Dict[str, EventSet]:
         month_range = self._get_arg_range(
             self.operator.month, self.operator.month_max_range()
         )
-        wday_range = self._get_arg_range(
-            self.operator.wday, self.operator.wday_max_range()
-        )
+
+        # Weekday: convert python (wday=0 for Mon) to C++ (wday=0 for Sun)
+        wday = self.operator.wday
+        if wday != "*":
+            wday = self._wday_py_to_cpp(wday)
+        wday_range = self._get_arg_range(wday, self.operator.wday_max_range())
 
         # Fill output EventSet's data
         for index_key, index_data in input.data.items():