diff --git a/apps/api/src/db/init-db.ts b/apps/api/src/db/init-db.ts
index 05f934c..334b999 100644
--- a/apps/api/src/db/init-db.ts
+++ b/apps/api/src/db/init-db.ts
@@ -90,6 +90,7 @@ export function initializeDatabase(sqlite: Database) {
       customer_id TEXT NOT NULL REFERENCES users(id),
       shipping_address_id TEXT NOT NULL REFERENCES addresses(id),
       status TEXT NOT NULL,
+      notes TEXT NOT NULL DEFAULT '',
       created_at TEXT NOT NULL,
       updated_at TEXT NOT NULL
     );
@@ -119,4 +120,8 @@ export function initializeDatabase(sqlite: Database) {
       created_at TEXT NOT NULL
     );
   `);
+
+  if (tableExists(sqlite, "orders") && !columnExists(sqlite, "orders", "notes")) {
+    sqlite.exec(`ALTER TABLE orders ADD COLUMN notes TEXT NOT NULL DEFAULT ''`);
+  }
 }
diff --git a/apps/api/src/db/schema/orders.ts b/apps/api/src/db/schema/orders.ts
index 2c31f07..2752a15 100644
--- a/apps/api/src/db/schema/orders.ts
+++ b/apps/api/src/db/schema/orders.ts
@@ -9,6 +9,7 @@ export const orders = sqliteTable("orders", {
   customerId: text("customer_id").notNull().references(() => users.id),
   shippingAddressId: text("shipping_address_id").notNull().references(() => addresses.id),
   status: text("status").notNull(),
+  notes: text("notes").notNull().default(""),
   createdAt: text("created_at").notNull(),
   updatedAt: text("updated_at").notNull()
 });
diff --git a/apps/api/src/orders/order-repository.ts b/apps/api/src/orders/order-repository.ts
index 20bc84c..4cec37d 100644
--- a/apps/api/src/orders/order-repository.ts
+++ b/apps/api/src/orders/order-repository.ts
@@ -96,6 +96,7 @@ export async function findOrderDetail(context: DatabaseContext, orderId: string)
     id: header.order.id,
     orderNumber: header.order.orderNumber,
     status: header.order.status as OrderDetail["status"],
+    notes: header.order.notes,
     createdAt: header.order.createdAt,
     updatedAt: header.order.updatedAt,
     customer: {
@@ -131,6 +132,10 @@ export async function updateOrderStatus(context: DatabaseContext, orderId: strin
   await context.db.update(orders).set({ status, updatedAt }).where(eq(orders.id, orderId));
 }
 
+export async function updateOrderNotes(context: DatabaseContext, orderId: string, notes: string, updatedAt: string) {
+  await context.db.update(orders).set({ notes, updatedAt }).where(eq(orders.id, orderId));
+}
+
 export async function updateOrderAddress(context: DatabaseContext, orderId: string, address: Address) {
   const [row] = await context.db.select({ shippingAddressId: orders.shippingAddressId }).from(orders).where(eq(orders.id, orderId));
 
diff --git a/apps/api/src/orders/order-routes.ts b/apps/api/src/orders/order-routes.ts
index ecb3b32..a1e7ff2 100644
--- a/apps/api/src/orders/order-routes.ts
+++ b/apps/api/src/orders/order-routes.ts
@@ -7,6 +7,7 @@ import { getOrder } from "./get-order";
 import { listAuditEvents } from "./list-audit-events";
 import { listOrders } from "./list-orders";
 import { changeOrderItemQuantity } from "./update-order-item";
+import { changeOrderNotes } from "./update-notes";
 import { changeShippingAddress } from "./update-shipping-address";
 
 interface OrderRouteOptions {
@@ -29,6 +30,10 @@ interface QuantityBody {
   quantity: number;
 }
 
+interface NotesBody {
+  notes: string;
+}
+
 interface CancelBody {
   reason?: string;
 }
@@ -95,6 +100,31 @@ export const registerOrderRoutes: FastifyPluginAsync<OrderRouteOptions> = async
     return result.order;
   });
 
+  app.post<{ Params: IdParams; Body: NotesBody }>("/orders/:orderId/notes", {
+    schema: {
+      body: {
+        type: "object",
+        required: ["notes"],
+        properties: {
+          notes: { type: "string" }
+        }
+      }
+    }
+  }, async (request, reply) => {
+    const currentUser = (request as AuthenticatedRequest).currentUser;
+    const result = await changeOrderNotes(options.db, {
+      orderId: request.params.orderId,
+      notes: request.body.notes,
+      actor: currentUser.username
+    });
+
+    if (result.statusCode !== 200) {
+      return reply.code(result.statusCode).send({ message: result.message });
+    }
+
+    return result.order;
+  });
+
   app.post<{ Params: IdParams; Body: Address }>("/orders/:orderId/shipping-address", {
     schema: {
       body: {
diff --git a/apps/api/src/orders/update-notes.ts b/apps/api/src/orders/update-notes.ts
new file mode 100644
index 0000000..5061328
--- /dev/null
+++ b/apps/api/src/orders/update-notes.ts
@@ -0,0 +1,44 @@
+import type { DatabaseContext } from "../db/database";
+import { appendAuditEvent, findOrderDetail, updateOrderNotes } from "./order-repository";
+
+export const NOTES_MAX_LENGTH = 1000;
+
+export async function changeOrderNotes(
+  context: DatabaseContext,
+  input: {
+    orderId: string;
+    notes: string;
+    actor: string;
+  }
+) {
+  const order = await findOrderDetail(context, input.orderId);
+
+  if (!order) {
+    return { statusCode: 404, message: "Order not found." } as const;
+  }
+
+  const notes = input.notes.trim();
+
+  if (notes.length === 0) {
+    return { statusCode: 400, message: "Notes cannot be empty." } as const;
+  }
+
+  if (notes.length > NOTES_MAX_LENGTH) {
+    return { statusCode: 400, message: `Notes cannot exceed ${NOTES_MAX_LENGTH} characters.` } as const;
+  }
+
+  const updatedAt = new Date().toISOString();
+  await updateOrderNotes(context, input.orderId, notes, updatedAt);
+  await appendAuditEvent(context, {
+    orderId: input.orderId,
+    actor: input.actor,
+    type: "order.notes_updated",
+    message: "Updated internal notes.",
+    createdAt: updatedAt
+  });
+
+  return {
+    statusCode: 200,
+    order: await findOrderDetail(context, input.orderId)
+  } as const;
+}
\ No newline at end of file
diff --git a/apps/web/src/orders/order-api.ts b/apps/web/src/orders/order-api.ts
index 957c8ef..838b637 100644
--- a/apps/web/src/orders/order-api.ts
+++ b/apps/web/src/orders/order-api.ts
@@ -28,6 +28,13 @@ export function updateShippingAddress(orderId: string, address: Address) {
   });
 }
 
+export function updateOrderNotes(orderId: string, notes: string) {
+  return apiRequest<OrderDetail>(`/api/orders/${orderId}/notes`, {
+    method: "POST",
+    body: JSON.stringify({ notes })
+  });
+}
+
 export function cancelOrder(orderId: string, reason?: string) {
   return apiRequest<OrderDetail>(`/api/orders/${orderId}/cancel`, {
     method: "POST",
diff --git a/apps/web/src/orders/order-detail-page.tsx b/apps/web/src/orders/order-detail-page.tsx
index 7387ded..92110a1 100644
--- a/apps/web/src/orders/order-detail-page.tsx
+++ b/apps/web/src/orders/order-detail-page.tsx
@@ -1,6 +1,7 @@
 import type { Address, AuditEvent, OrderDetail } from "@orderops/shared";
 import { AuditTimeline } from "./audit-timeline";
 import { OrderItemsPanel } from "./order-items-panel";
+import { OrderNotesPanel } from "./order-notes";
 import { OrderSummaryPanel } from "./order-summary";
 import { ShippingAddressForm } from "./shipping-address-form";
 
@@ -9,6 +10,7 @@ interface OrderDetailPageProps {
   auditEvents: AuditEvent[];
   onUpdateQuantity: (itemId: string, quantity: number) => Promise<void>;
   onSaveAddress: (address: Address) => Promise<void>;
+  onSaveNotes: (notes: string) => Promise<void>;
   onCancel: () => Promise<void>;
 }
 
@@ -17,11 +19,13 @@ export function OrderDetailPage({
   auditEvents,
   onUpdateQuantity,
   onSaveAddress,
+  onSaveNotes,
   onCancel
 }: OrderDetailPageProps) {
   return (
     <div className="space-y-4">
       <OrderSummaryPanel order={order} />
+      <OrderNotesPanel notes={order.notes} onSave={onSaveNotes} />
       <div className="flex justify-end">
         <button className="rounded-md bg-red-600 px-4 py-2 text-sm font-medium text-white" onClick={() => void onCancel()} type="button">
           Cancel order
diff --git a/apps/web/src/orders/order-notes.tsx b/apps/web/src/orders/order-notes.tsx
new file mode 100644
index 0000000..91498ac
--- /dev/null
+++ b/apps/web/src/orders/order-notes.tsx
@@ -0,0 +1,60 @@
+import { useState } from "react";
+
+export const NOTES_MAX_LENGTH = 1000;
+
+interface OrderNotesProps {
+  notes: string;
+  onSave: (notes: string) => Promise<void>;
+}
+
+export function OrderNotesPanel({ notes, onSave }: OrderNotesProps) {
+  const [draft, setDraft] = useState(notes);
+  const [isSaving, setIsSaving] = useState(false);
+  const trimmed = draft.trim();
+  const isDisabled = isSaving || trimmed.length === 0 || trimmed === notes;
+
+  async function handleSave() {
+    if (isDisabled) {
+      return;
+    }
+
+    setIsSaving(true);
+    try {
+      await onSave(trimmed);
+    } finally {
+      setIsSaving(false);
+    }
+  }
+
+  return (
+    <section className="rounded-xl border border-slate-200 bg-white p-4 shadow-sm">
+      <div className="mb-3 flex items-center justify-between">
+        <h3 className="text-sm font-semibold text-slate-700">Internal notes</h3>
+        <span className="text-xs text-slate-500">{draft.length}/{NOTES_MAX_LENGTH}</span>
+      </div>
+      {notes ? (
+        <p className="mb-3 whitespace-pre-wrap text-sm text-slate-700">{notes}</p>
+      ) : (
+        <p className="mb-3 text-sm text-slate-400">No internal notes yet. Add context for teammates following up on this order.</p>
+      )}
+      <textarea
+        className="w-full resize-y rounded-lg border border-slate-300 px-3 py-2 text-sm text-slate-900 focus:border-blue-500 focus:outline-none"
+        maxLength={NOTES_MAX_LENGTH}
+        onChange={(event) => setDraft(event.target.value)}
+        placeholder="Add internal notes..."
+        rows={3}
+        value={draft}
+      />
+      <div className="mt-3 flex justify-end">
+        <button
+          className="rounded-md bg-blue-600 px-4 py-2 text-sm font-medium text-white disabled:cursor-not-allowed disabled:opacity-50"
+          disabled={isDisabled}
+          onClick={() => void handleSave()}
+          type="button"
+        >
+          {isSaving ? "Saving..." : "Save notes"}
+        </button>
+      </div>
+    </section>
+  );
+}
\ No newline at end of file
diff --git a/apps/web/src/orders/order-page.tsx b/apps/web/src/orders/order-page.tsx
index 988e31a..2a4db8b 100644
--- a/apps/web/src/orders/order-page.tsx
+++ b/apps/web/src/orders/order-page.tsx
@@ -2,7 +2,7 @@ import { useEffect, useState } from "react";
 import type { Address, AuditEvent, OrderDetail } from "@orderops/shared";
 import { Link, useParams } from "react-router-dom";
 import { Toast } from "../ui/toast";
-import { cancelOrder, getOrder, listAuditEvents, updateOrderItemQuantity, updateShippingAddress } from "./order-api";
+import { cancelOrder, getOrder, listAuditEvents, updateOrderItemQuantity, updateOrderNotes, updateShippingAddress } from "./order-api";
 import { OrderDetailPage } from "./order-detail-page";
 
 interface ToastState {
@@ -86,6 +86,7 @@ export function OrderPage() {
           auditEvents={auditEvents}
           onUpdateQuantity={(itemId, quantity) => runAction(() => updateOrderItemQuantity(order.id, itemId, quantity), "Quantity saved.")}
           onSaveAddress={(address: Address) => runAction(() => updateShippingAddress(order.id, address), "Shipping address saved.")}
+          onSaveNotes={(notes: string) => runAction(() => updateOrderNotes(order.id, notes), "Notes saved.")}
           onCancel={() => runAction(() => cancelOrder(order.id), "Order cancelled.")}
         />
       ) : null}
diff --git a/packages/shared/src/order-detail.ts b/packages/shared/src/order-detail.ts
index f204ce2..a4e068c 100644
--- a/packages/shared/src/order-detail.ts
+++ b/packages/shared/src/order-detail.ts
@@ -17,6 +17,7 @@ export interface OrderDetail {
   id: string;
   orderNumber: string;
   status: OrderStatus;
+  notes: string;
   createdAt: string;
   updatedAt: string;
   customer: CustomerSummary;