diff --git a/homeassistant/components/todoist/calendar.py b/homeassistant/components/todoist/calendar.py
index 1188831c26d..b9ab4fe6dbb 100644
--- a/homeassistant/components/todoist/calendar.py
+++ b/homeassistant/components/todoist/calendar.py
@@ -226,15 +226,14 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
     )
 
 
-def _parse_due_date(data: dict) -> datetime:
+def _parse_due_date(data: dict, gmt_string) -> datetime:
     """Parse the due date dict into a datetime object."""
     # Add time information to date only strings.
     if len(data["date"]) == 10:
         data["date"] += "T00:00:00"
-    # If there is no timezone provided, use UTC.
-    if data["timezone"] is None:
-        data["date"] += "Z"
-    return dt.parse_datetime(data["date"])
+    if dt.parse_datetime(data["date"]).tzinfo is None:
+        data["date"] += gmt_string
+    return dt.as_utc(dt.parse_datetime(data["date"]))
 
 
 class TodoistProjectDevice(CalendarEventDevice):
@@ -407,7 +406,9 @@ class TodoistProjectData:
         # Generally speaking, that means right now.
         task[START] = dt.utcnow()
         if data[DUE] is not None:
-            task[END] = _parse_due_date(data[DUE])
+            task[END] = _parse_due_date(
+                data[DUE], self._api.state["user"]["tz_info"]["gmt_string"]
+            )
 
             if self._due_date_days is not None and (
                 task[END] > dt.utcnow() + self._due_date_days
@@ -529,9 +530,19 @@ class TodoistProjectData:
         for task in project_task_data:
             if task["due"] is None:
                 continue
-            due_date = _parse_due_date(task["due"])
+            due_date = _parse_due_date(
+                task["due"], self._api.state["user"]["tz_info"]["gmt_string"]
+            )
+            midnight = dt.as_utc(
+                dt.parse_datetime(
+                    due_date.strftime("%Y-%m-%d")
+                    + "T00:00:00"
+                    + self._api.state["user"]["tz_info"]["gmt_string"]
+                )
+            )
+
             if start_date < due_date < end_date:
-                if due_date.hour == 0 and due_date.minute == 0:
+                if due_date == midnight:
                     # If the due date has no time data, return just the date so that it
                     # will render correctly as an all day event on a calendar.
                     due_date_value = due_date.strftime("%Y-%m-%d")