diff --git a/.gitignore b/.gitignore
index 311312a3..25e71042 100644
--- a/.gitignore
+++ b/.gitignore
@@ -28,3 +28,5 @@ betterseqtaplus-safari/
 .env.submit
 dependency-graph.svg
 
+update-videos/
+
diff --git a/src/resources/calendar-sync-update.mp4 b/src/resources/calendar-sync-update.mp4
new file mode 100644
index 00000000..03241908
Binary files /dev/null and b/src/resources/calendar-sync-update.mp4 differ
diff --git a/src/seqta/utils/googleCalendar/eventColor.test.ts b/src/seqta/utils/googleCalendar/eventColor.test.ts
new file mode 100644
index 00000000..1e664b78
--- /dev/null
+++ b/src/seqta/utils/googleCalendar/eventColor.test.ts
@@ -0,0 +1,22 @@
+import { describe, expect, it } from "@jest/globals";
+import { nearestGoogleEventColorId } from "./eventColor";
+
+describe("nearestGoogleEventColorId", () => {
+  it("returns undefined for empty input", () => {
+    expect(nearestGoogleEventColorId(undefined)).toBeUndefined();
+    expect(nearestGoogleEventColorId("")).toBeUndefined();
+  });
+
+  it("maps a red subject colour to Tomato", () => {
+    expect(nearestGoogleEventColorId("#dc2127")).toBe("11");
+    expect(nearestGoogleEventColorId("#E76F51")).toBe("4");
+  });
+
+  it("maps a green subject colour to Basil or Sage", () => {
+    expect(["2", "10"]).toContain(nearestGoogleEventColorId("#51b749"));
+  });
+
+  it("accepts rgb() values", () => {
+    expect(nearestGoogleEventColorId("rgb(220, 33, 39)")).toBe("11");
+  });
+});
diff --git a/src/seqta/utils/googleCalendar/eventColor.ts b/src/seqta/utils/googleCalendar/eventColor.ts
new file mode 100644
index 00000000..497ac9c8
--- /dev/null
+++ b/src/seqta/utils/googleCalendar/eventColor.ts
@@ -0,0 +1,90 @@
+/** Google Calendar event palette (`colorId` → background). */
+export const GOOGLE_EVENT_COLORS: ReadonlyArray<{ id: string; background: string }> = [
+  { id: "1", background: "#a4bdfc" },
+  { id: "2", background: "#7ae7bf" },
+  { id: "3", background: "#dbadff" },
+  { id: "4", background: "#ff887c" },
+  { id: "5", background: "#fbd75b" },
+  { id: "6", background: "#ffb878" },
+  { id: "7", background: "#46d6db" },
+  { id: "8", background: "#e1e1e1" },
+  { id: "9", background: "#5484ed" },
+  { id: "10", background: "#51b749" },
+  { id: "11", background: "#dc2127" },
+];
+
+type Rgb = { r: number; g: number; b: number };
+
+function expandHex(hex: string): string | null {
+  const raw = hex.replace("#", "").trim();
+  if (/^[0-9a-fA-F]{3}$/.test(raw)) {
+    return raw
+      .split("")
+      .map((ch) => ch + ch)
+      .join("");
+  }
+  if (/^[0-9a-fA-F]{6}$/.test(raw)) return raw;
+  if (/^[0-9a-fA-F]{8}$/.test(raw)) return raw.slice(0, 6);
+  return null;
+}
+
+/** Parse common CSS colour strings to RGB (hex / rgb / rgba). */
+export function parseRgbColour(value: string): Rgb | null {
+  const trimmed = value.trim();
+  if (!trimmed) return null;
+
+  const hexMatch = trimmed.match(/#([0-9a-fA-F]{3,8})\b/);
+  if (hexMatch) {
+    const expanded = expandHex(hexMatch[1]!);
+    if (!expanded) return null;
+    return {
+      r: Number.parseInt(expanded.slice(0, 2), 16),
+      g: Number.parseInt(expanded.slice(2, 4), 16),
+      b: Number.parseInt(expanded.slice(4, 6), 16),
+    };
+  }
+
+  const rgbMatch = trimmed.match(
+    /rgba?\(\s*([\d.]+)\s*,\s*([\d.]+)\s*,\s*([\d.]+)/i,
+  );
+  if (rgbMatch) {
+    return {
+      r: Math.round(Number(rgbMatch[1])),
+      g: Math.round(Number(rgbMatch[2])),
+      b: Math.round(Number(rgbMatch[3])),
+    };
+  }
+
+  return null;
+}
+
+function rgbDistance(a: Rgb, b: Rgb): number {
+  const dr = a.r - b.r;
+  const dg = a.g - b.g;
+  const db = a.b - b.b;
+  return dr * dr + dg * dg + db * db;
+}
+
+/**
+ * Maps a SEQTA subject colour to the nearest Google Calendar event `colorId`.
+ * Returns undefined when the colour cannot be parsed.
+ */
+export function nearestGoogleEventColorId(colour: string | undefined): string | undefined {
+  const target = colour ? parseRgbColour(colour) : null;
+  if (!target) return undefined;
+
+  let bestId: string | undefined;
+  let bestDistance = Number.POSITIVE_INFINITY;
+
+  for (const entry of GOOGLE_EVENT_COLORS) {
+    const candidate = parseRgbColour(entry.background);
+    if (!candidate) continue;
+    const distance = rgbDistance(target, candidate);
+    if (distance < bestDistance) {
+      bestDistance = distance;
+      bestId = entry.id;
+    }
+  }
+
+  return bestId;
+}
diff --git a/src/seqta/utils/googleCalendar/eventMapper.test.ts b/src/seqta/utils/googleCalendar/eventMapper.test.ts
index 7db17c67..ef344fcc 100644
--- a/src/seqta/utils/googleCalendar/eventMapper.test.ts
+++ b/src/seqta/utils/googleCalendar/eventMapper.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, it } from "@jest/globals";
 import {
+  googleApiEventBody,
   lessonToGoogleEvent,
   mapLessonsToGoogleEvents,
   outlookGraphEventBody,
@@ -51,6 +52,27 @@ describe("lessonToGoogleEvent", () => {
     });
     expect(event?.description).toContain("Mr Smith");
   });
+
+  it("maps subject colour to a Google colorId", () => {
+    const event = lessonToGoogleEvent(
+      ORIGIN,
+      { ...baseLesson, colour: "#dc2127" },
+      "Australia/Perth",
+    );
+    expect(event?.colorId).toBe("11");
+  });
+});
+
+describe("googleApiEventBody", () => {
+  it("includes colorId when present", () => {
+    const event = lessonToGoogleEvent(
+      ORIGIN,
+      { ...baseLesson, colour: "#dc2127" },
+      "Australia/Perth",
+    );
+    expect(event).not.toBeNull();
+    expect(googleApiEventBody(event!)).toMatchObject({ colorId: "11" });
+  });
 });
 
 describe("mapLessonsToGoogleEvents", () => {
diff --git a/src/seqta/utils/googleCalendar/eventMapper.ts b/src/seqta/utils/googleCalendar/eventMapper.ts
index 755110b8..45dfe248 100644
--- a/src/seqta/utils/googleCalendar/eventMapper.ts
+++ b/src/seqta/utils/googleCalendar/eventMapper.ts
@@ -1,6 +1,7 @@
 import { BSPLUS_GOOGLE_CALENDAR_EVENT_PROP } from "@/config/googleCalendar";
 import { BSPLUS_OUTLOOK_CALENDAR_EVENT_CATEGORY } from "@/config/outlookCalendar";
 import { outlookDescriptionWithKey } from "@/seqta/utils/calendarSync/eventFingerprint";
+import { nearestGoogleEventColorId } from "./eventColor";
 import type { GoogleCalendarEventInput, SeqtaTimetableLesson } from "./types";
 
 const SKIP_TYPES = new Set(["note", "holiday", "assembly-note"]);
@@ -54,6 +55,8 @@ export function lessonToGoogleEvent(
   if (lesson.code) descriptionLines.push(`Code: ${lesson.code}`);
   if (lesson.period) descriptionLines.push(`Period: ${lesson.period}`);
 
+  const colorId = nearestGoogleEventColorId(lesson.colour);
+
   return {
     seqtaKey: seqtaLessonKey(origin, lesson),
     summary,
@@ -62,6 +65,7 @@ export function lessonToGoogleEvent(
     startDateTime: `${lesson.date}T${from}:00`,
     endDateTime: `${lesson.date}T${until}:00`,
     timeZone,
+    ...(colorId ? { colorId } : {}),
   };
 }
 
@@ -82,7 +86,7 @@ export function mapLessonsToGoogleEvents(
 }
 
 export function googleApiEventBody(event: GoogleCalendarEventInput): Record<string, unknown> {
-  return {
+  const body: Record<string, unknown> = {
     summary: event.summary,
     location: event.location,
     description: event.description,
@@ -94,6 +98,10 @@ export function googleApiEventBody(event: GoogleCalendarEventInput): Record<stri
       },
     },
   };
+  if (event.colorId) {
+    body.colorId = event.colorId;
+  }
+  return body;
 }
 
 export function outlookGraphEventBody(event: GoogleCalendarEventInput): Record<string, unknown> {
diff --git a/src/seqta/utils/googleCalendar/fetchTimetable.ts b/src/seqta/utils/googleCalendar/fetchTimetable.ts
index f5c7444b..7d2a6427 100644
--- a/src/seqta/utils/googleCalendar/fetchTimetable.ts
+++ b/src/seqta/utils/googleCalendar/fetchTimetable.ts
@@ -2,6 +2,8 @@ import type { SyncDateRange } from "./syncDateRange";
 import { syncWindowRange } from "./syncDateRange";
 import type { SeqtaTimetableLesson } from "./types";
 
+type PrefItem = { name?: string; value?: string };
+
 async function postSeqtaJson<T>(path: string, body: Record<string, unknown>): Promise<T> {
   const res = await fetch(`${location.origin}${path}`, {
     method: "POST",
@@ -19,6 +21,54 @@ async function postSeqtaJson<T>(path: string, body: Record<string, unknown>): Pr
   return (await res.json()) as T;
 }
 
+function prefsToSubjectColours(prefs: PrefItem[] | undefined): Record<string, string> {
+  const colours: Record<string, string> = {};
+  for (const pref of prefs ?? []) {
+    if (!pref.name?.startsWith("timetable.subject.colour.") || !pref.value) continue;
+    const code = pref.name.slice("timetable.subject.colour.".length);
+    if (code) colours[code] = pref.value;
+  }
+  return colours;
+}
+
+async function fetchSubjectColours(): Promise<Record<string, string>> {
+  try {
+    if (isEngageParentContext()) {
+      const data = await postSeqtaJson<{ payload?: PrefItem[] }>("/seqta/parent/load/prefs?", {
+        request: "userPrefs",
+        asArray: true,
+      });
+      return prefsToSubjectColours(data?.payload);
+    }
+
+    const studentId = await resolveStudentId();
+    const body: Record<string, unknown> = {
+      request: "userPrefs",
+      asArray: true,
+    };
+    if (studentId != null) body.user = studentId;
+
+    const data = await postSeqtaJson<{ payload?: PrefItem[] }>("/seqta/student/load/prefs?", body);
+    return prefsToSubjectColours(data?.payload);
+  } catch {
+    return {};
+  }
+}
+
+function withSubjectColours(
+  lessons: SeqtaTimetableLesson[],
+  colours: Record<string, string>,
+): SeqtaTimetableLesson[] {
+  if (Object.keys(colours).length === 0) return lessons;
+  return lessons.map((lesson) => {
+    const code = lesson.code?.trim();
+    if (!code) return lesson;
+    const colour = colours[code];
+    if (!colour) return lesson;
+    return { ...lesson, colour };
+  });
+}
+
 export async function resolveStudentId(): Promise<number | undefined> {
   try {
     const json = await postSeqtaJson<{ payload?: { id?: number; student?: number } }>(
@@ -44,6 +94,9 @@ export async function fetchTimetableLessons(
   range: SyncDateRange,
 ): Promise<SeqtaTimetableLesson[]> {
   const { from, until } = range;
+  const coloursPromise = fetchSubjectColours();
+
+  let lessons: SeqtaTimetableLesson[] = [];
 
   if (isEngageParentContext()) {
     const listJson = await postSeqtaJson<{ payload?: { id?: string | number }[] }>(
@@ -59,18 +112,20 @@ export async function fetchTimetableLessons(
       "/seqta/parent/load/timetable",
       { from, until, student: studentId },
     );
-    return Array.isArray(data?.payload?.items) ? data.payload.items : [];
+    lessons = Array.isArray(data?.payload?.items) ? data.payload.items : [];
+  } else {
+    const studentId = await resolveStudentId();
+    const body: Record<string, unknown> = { from, until };
+    if (studentId != null) body.student = studentId;
+
+    const data = await postSeqtaJson<{ payload?: { items?: SeqtaTimetableLesson[] } }>(
+      "/seqta/student/load/timetable?",
+      body,
+    );
+    lessons = Array.isArray(data?.payload?.items) ? data.payload.items : [];
   }
 
-  const studentId = await resolveStudentId();
-  const body: Record<string, unknown> = { from, until };
-  if (studentId != null) body.student = studentId;
-
-  const data = await postSeqtaJson<{ payload?: { items?: SeqtaTimetableLesson[] } }>(
-    "/seqta/student/load/timetable?",
-    body,
-  );
-  return Array.isArray(data?.payload?.items) ? data.payload.items : [];
+  return withSubjectColours(lessons, await coloursPromise);
 }
 
 export async function fetchTimetableForSync(weeksAhead?: number): Promise<SeqtaTimetableLesson[]> {
diff --git a/src/seqta/utils/googleCalendar/types.ts b/src/seqta/utils/googleCalendar/types.ts
index c7c14465..210d4876 100644
--- a/src/seqta/utils/googleCalendar/types.ts
+++ b/src/seqta/utils/googleCalendar/types.ts
@@ -10,6 +10,8 @@ export interface SeqtaTimetableLesson {
   period?: string;
   calendarid?: string | number;
   ci?: number;
+  /** SEQTA subject colour (hex/rgb) used for Google Calendar event colour. */
+  colour?: string;
 }
 
 export interface GoogleCalendarEventInput {
@@ -20,6 +22,8 @@ export interface GoogleCalendarEventInput {
   startDateTime: string;
   endDateTime: string;
   timeZone: string;
+  /** Google Calendar event colorId ("1"–"11"). */
+  colorId?: string;
 }
 
 export interface GoogleCalendarSyncRequest {