diff --git a/src/ifc4d/README.md b/src/ifc4d/README.md
index 658eadc531..306ca87893 100644
--- a/src/ifc4d/README.md
+++ b/src/ifc4d/README.md
@@ -7,10 +7,10 @@ Ifc4D contains a series of utilities for converting to and from various 4D softw
  - Oracle Primavera 6 (P6) XER to IFC
  - Asta Powerproject to IFC
  - IFC to Oracle Primavera 6 (P6) XML
+ - IFC to Microsoft Project
 
 Planned (would you like to contribute? Please reach out!):
 
- - IFC to Microsoft Project
  - IFC to Oracle Primavera 6 (P6) XER
  - IFC to Oracle Primavera 6 (P6) XLS
  - IFC to Asta Powerproject
@@ -21,3 +21,6 @@ Planned (would you like to contribute? Please reach out!):
 ## Useful links
 
  - [P6 EPPM XER Import/Export Data Map Guide](https://docs.oracle.com/cd/F12057_01/English/Mapping_and_Schema/xer_import_export_data_map_project/helpmain.htm?toc.htm?97881.htm)
+ - [Microsoft Project 2007 XML XSD](https://schemas.microsoft.com/project/2007/mspdi_pj12.xsd)
+ - [Microsoft Project XML Documentation](https://docs.microsoft.com/en-us/office-project/xml-data-interchange/project-xml-data-interchange-schema-reference?view=project-client-2016)
+ - [Microsoft Project 2010 SDK Download](https://www.microsoft.com/en-us/download/details.aspx?id=15511) (needed to get `mspdi_pj14.xsd`)
diff --git a/src/ifc4d/ifc4d/ifc2msp.py b/src/ifc4d/ifc4d/ifc2msp.py
new file mode 100644
index 0000000000..9577e2eb00
--- /dev/null
+++ b/src/ifc4d/ifc4d/ifc2msp.py
@@ -0,0 +1,269 @@
+# Ifc4D - IFC scheduling utility
+# Copyright (C) 2022 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of Ifc4D.
+#
+# Ifc4D is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Ifc4D is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with Ifc4D.  If not, see <http://www.gnu.org/licenses/>.
+
+import uuid
+import datetime
+import ifcopenshell
+import ifcopenshell.util.date
+import xml.etree.ElementTree as ET
+
+
+class Ifc2Msp:
+    def __init__(self):
+        self.xml = None
+        self.file = None
+        self.id = 0
+        self.id_map = {}
+        self.element_map = {}
+        self.hours_per_day = 8
+        self.project_tasks = []
+        self.start_dates = []
+        self.base_calendar = None
+        # P6XML does not understand patterns in holiday dates. Instead, it
+        # expects a list of every day that is a holiday between a date range.
+        # This allows you to specify the date range where the export should
+        # calculate holidays for.
+        self.holiday_start_date = None
+        self.holiday_finish_date = None
+        self.work_schedule = None
+
+    def execute(self):
+        self.root = ET.Element("Project")
+        self.root.attrib["xmlns"] = "http://schemas.microsoft.com/project"
+
+        self.schedule = self.file.by_type("IfcWorkSchedule")[0]
+
+        self.create_project()
+        self.create_calendars()
+        self.create_tasks()
+
+        self.set_start_date()
+        self.set_base_calendar()
+
+        tree = ET.ElementTree(self.root)
+        tree.write(self.xml, encoding="utf-8", xml_declaration=True)
+
+    def create_project(self):
+        # Which version should we pick? I don't know. Hardcode as 14 until it breaks :)
+        # Values are: 12=Project 2007, 24=Project 2010
+        ET.SubElement(self.root, "SaveVersion").text = "14"
+        element = self.file.by_type("IfcProject")[0]
+        self.link_element(element, self.root)
+        ET.SubElement(self.root, "GUID").text = str(uuid.UUID(ifcopenshell.guid.expand(element.GlobalId))).upper()
+        ET.SubElement(self.root, "Name").text = element.Name or "X"
+        ET.SubElement(self.root, "Title").text = element.LongName or "Unnamed"
+        # This is mandatory, but we don't use it
+        ET.SubElement(self.root, "CurrencyCode").text = "USD"
+        ET.SubElement(self.root, "DurationFormat").text = "7"
+        ET.SubElement(self.root, "MinutesPerDay").text = "480"
+
+    def set_start_date(self):
+        ET.SubElement(self.root, "ScheduleFromStart").text = "1"
+        if self.start_dates:
+            # Set to midnight as a workaround. If I don't, the first duration seems to stick to zero.
+            ET.SubElement(self.root, "StartDate").text = sorted(self.start_dates)[0].split("T")[0] + "T00:00:00"
+
+    def set_base_calendar(self):
+        if self.base_calendar:
+            ET.SubElement(self.root, "CalendarUID").text = self.id_map[self.base_calendar]
+
+    def create_calendars(self):
+        el = ET.SubElement(self.root, "Calendars")
+        for calendar in self.file.by_type("IfcWorkCalendar"):
+            self.create_calendar(calendar, el)
+
+    def create_calendar(self, calendar, parent):
+        el = ET.SubElement(parent, "Calendar")
+        self.link_element(calendar, el)
+        ET.SubElement(el, "Name").text = calendar.Name or "Unnamed"
+        ET.SubElement(el, "IsBaseCalendar").text = "1"
+
+        working_week = self.auto_detect_working_week(calendar)
+
+        if not working_week:
+            working_week = self.get_default_working_week()
+
+        week_days = ET.SubElement(el, "WeekDays")
+
+        day_map = {
+            "Sunday": "1",
+            "Monday": "2",
+            "Tuesday": "3",
+            "Wednesday": "4",
+            "Thursday": "5",
+            "Friday": "6",
+            "Saturday": "7",
+        }
+
+        for day in ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"]:
+            time_periods = working_week.get(day, None)
+            if time_periods:
+                week_day = ET.SubElement(week_days, "WeekDay")
+                ET.SubElement(week_day, "DayType").text = day_map[day]
+                ET.SubElement(week_day, "DayWorking").text = "1"
+                working_times = ET.SubElement(week_day, "WorkingTimes")
+                for time_period in time_periods:
+                    working_time = ET.SubElement(working_times, "WorkingTime")
+                    ET.SubElement(working_time, "FromTime").text = time_period["Start"]
+                    ET.SubElement(working_time, "ToTime").text = time_period["Finish"]
+            else:
+                week_day = ET.SubElement(week_days, "WeekDay")
+                ET.SubElement(week_day, "DayType").text = day_map[day]
+                ET.SubElement(week_day, "DayWorking").text = "0"
+
+        # TODO Exceptions not yet implemented
+        return
+
+        holidays = ET.SubElement(el, "Exceptions")
+        for holiday in self.auto_detect_holidays(calendar):
+            el = ET.SubElement(holidays, "Exception")
+            # Recurrence is supported but I haven't implemented it yet
+            holiday = ifcopenshell.util.date.datetime2ifc(holiday, "IfcDateTime")
+            time_period = ET.SubElement(el, "TimePeriod")
+            ET.SubElement(time_period, "FromDate").text = holiday
+            ET.SubElement(time_period, "ToDate").text = holiday
+
+    def auto_detect_working_week(self, calendar):
+        # Microsoft Project XML only understands a working week. In other words,
+        # it understands the equivalent of an IFC weekly recurring time period.
+        # If you do not have a weekly recurring time period, we just give a
+        # default working week.
+        results = {}
+        weekday_component_map = {
+            1: "Monday",
+            2: "Tuesday",
+            3: "Wednesday",
+            4: "Thursday",
+            5: "Friday",
+            6: "Saturday",
+            7: "Sunday",
+        }
+        for working_time in calendar.WorkingTimes:
+            if not working_time.RecurrencePattern or working_time.RecurrencePattern.RecurrenceType != "WEEKLY":
+                continue
+
+            if not working_time.RecurrencePattern.TimePeriods:
+                time_periods = [{"Start": "09:00:00", "Finish": "17:00:00"}]
+            else:
+                time_periods = [
+                    {"Start": p.StartTime, "Finish": p.EndTime} for p in working_time.RecurrencePattern.TimePeriods
+                ]
+
+            for component in working_time.RecurrencePattern.WeekdayComponent:
+                results.setdefault(weekday_component_map[component], []).extend(time_periods)
+
+        return results
+
+    def get_default_working_week(self):
+        results = {}
+        # As a fallback, we work 5 days a week, 8 hours per day.
+        for name in ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]:
+            results[name] = [{"Start": "09:00:00", "Finish": "17:00:00"}]
+        return results
+
+    def auto_detect_holidays(self, calendar):
+        results = []
+        start = self.holiday_start_date
+        finish = self.holiday_finish_date
+        if finish < start:
+            return results
+        while start < finish:
+            start += datetime.timedelta(days=1)
+            if not ifcopenshell.util.sequence.is_working_day(start, calendar):
+                results.append(start)
+        return results
+
+    def create_tasks(self):
+        self.tasks = ET.SubElement(self.root, "Tasks")
+        for task in self.get_subtasks(self.work_schedule):
+            self.create_task(task)
+
+    def create_task(self, task, level=0):
+        el = ET.SubElement(self.tasks, "Task")
+        self.link_element(task, el)
+        ET.SubElement(el, "Name").text = task.Name or "Unnamed"
+        ET.SubElement(el, "OutlineNumber").text = task.Identification or "X"
+        ET.SubElement(el, "OutlineLevel").text = str(level)
+        ET.SubElement(el, "DurationFormat").text = "53"
+        if task.TaskTime:
+            if task.TaskTime.ScheduleDuration:
+                duration = ifcopenshell.util.date.ifc2datetime(task.TaskTime.ScheduleDuration)
+                ET.SubElement(el, "Duration").text = f"PT{duration.days * 8}H0M0S"
+            if task.TaskTime.ScheduleStart:
+                ET.SubElement(el, "Start").text = task.TaskTime.ScheduleStart
+                self.start_dates.append(task.TaskTime.ScheduleStart)
+            if task.TaskTime.ScheduleFinish:
+                ET.SubElement(el, "Finish").text = task.TaskTime.ScheduleFinish
+            ET.SubElement(el, "Critical").text = "1" if task.TaskTime.IsCritical else "0"
+
+            data_map = {
+                "EarlyStart": task.TaskTime.EarlyStart,
+                "EarlyFinish": task.TaskTime.EarlyFinish,
+                "LateStart": task.TaskTime.LateStart,
+                "LateFinish": task.TaskTime.LateFinish,
+            }
+            for key, value in data_map.items():
+                if value:
+                    ET.SubElement(el, key).text = value
+
+        calendar = ifcopenshell.util.sequence.derive_calendar(task)
+        if calendar:
+            ET.SubElement(el, "CalendarUID").text = self.id_map[calendar]
+            if level == 0:
+                # This must be the base calendar
+                self.base_calendar = calendar
+
+        for rel in task.IsSuccessorFrom or []:
+            predecessor = rel.RelatingProcess
+            predecessor_link = ET.SubElement(el, "PredecessorLink")
+            self.link_element(rel, predecessor_link)
+            if rel.TimeLag and rel.TimeLag.LagValue:
+                duration = ifcopenshell.util.date.ifc2datetime(rel.TimeLag.LagValue.wrappedValue)
+                # Lag time is expressed in tenths of a minute. Seriously, Microsoft?
+                ET.SubElement(predecessor_link, "LinkLag").text = str(duration.days * self.hours_per_day * 60 * 10)
+            else:
+                ET.SubElement(predecessor_link, "LinkLag").text = "0"
+            ET.SubElement(predecessor_link, "PredecessorUID").text = str(predecessor.id())
+            ET.SubElement(predecessor_link, "Type").text = {
+                "START_START": "3",
+                "START_FINISH": "2",
+                "FINISH_START": "1",
+                "FINISH_FINISH": "0",
+                "NOTDEFINED": "1",
+                "USERDEFINED": "1",
+                None: "1",
+            }[rel.SequenceType]
+
+        for subtask in self.get_subtasks(task):
+            self.create_task(subtask, level=level + 1)
+
+    def get_subtasks(self, element):
+        tasks = []
+        if element.is_a("IfcWorkSchedule"):
+            for rel in element.Controls or []:
+                tasks.extend([e for e in rel.RelatedObjects if e.is_a("IfcTask")])
+        elif element.is_a("IfcTask"):
+            for rel in element.IsNestedBy or []:
+                tasks.extend([e for e in rel.RelatedObjects if e.is_a("IfcTask")])
+        return tasks
+
+    def link_element(self, element, el):
+        ET.SubElement(el, "UID").text = str(element.id())
+        ET.SubElement(el, "GUID").text = str(uuid.UUID(ifcopenshell.guid.expand(element.GlobalId))).upper()
+        self.id_map[element] = str(element.id())
+        self.element_map[element] = el