diff --git a/src/lib/server/db/schema.ts b/src/lib/server/db/schema.ts
index a05a755..86e54ae 100644
--- a/src/lib/server/db/schema.ts
+++ b/src/lib/server/db/schema.ts
@@ -130,6 +130,9 @@ export const expenses = pgTable(
 		accountId: uuid('account_id').references((): any => companyAccounts.id, {
 			onDelete: 'set null'
 		}),
+		invoiceId: uuid('invoice_id').references((): any => invoices.id, {
+			onDelete: 'set null'
+		}),
 		submittedBy: text('submitted_by')
 			.notNull()
 			.references(() => users.id),
diff --git a/src/routes/(app)/companies/[companyId]/expenses/+page.server.ts b/src/routes/(app)/companies/[companyId]/expenses/+page.server.ts
index d4bebac..8622a10 100644
--- a/src/routes/(app)/companies/[companyId]/expenses/+page.server.ts
+++ b/src/routes/(app)/companies/[companyId]/expenses/+page.server.ts
@@ -6,9 +6,11 @@ import {
 	projects,
 	users,
 	categories,
-	companyAccounts
+	companyAccounts,
+	invoices,
+	parties
 } from '$lib/server/db/schema.js';
-import { asc, eq, and, sql, isNull } from 'drizzle-orm';
+import { asc, eq, and, ne, sql, isNull } from 'drizzle-orm';
 import { requireCompanyRole, requireCompanyRoleAny } from '$lib/server/authorization.js';
 import { logCompanyEvent } from '$lib/server/audit.js';
 import { formatCurrency } from '$lib/utils/currency.js';
@@ -40,6 +42,7 @@ export const load: PageServerLoad = async ({ parent, params, url }) => {
 			categoryName: categories.name,
 			accountId: expenses.accountId,
 			accountName: companyAccounts.name,
+			invoiceId: expenses.invoiceId,
 			createdAt: expenses.createdAt
 		})
 		.from(expenses)
@@ -87,12 +90,33 @@ export const load: PageServerLoad = async ({ parent, params, url }) => {
 		.where(eq(categories.companyId, params.companyId))
 		.orderBy(asc(categories.name));
 
+	const invoiceList = await db
+		.select({
+			id: invoices.id,
+			invoiceNumber: invoices.invoiceNumber,
+			direction: invoices.direction,
+			partyName: parties.name,
+			total: invoices.total,
+			currency: invoices.currency
+		})
+		.from(invoices)
+		.innerJoin(parties, eq(invoices.partyId, parties.id))
+		.where(
+			and(
+				eq(invoices.companyId, params.companyId),
+				ne(invoices.status, 'voided'),
+				ne(invoices.status, 'cancelled')
+			)
+		)
+		.orderBy(asc(invoices.invoiceNumber));
+
 	return {
 		expenses: expenseList,
 		statusFilter: status,
 		accounts: accountsList,
 		projects: projectList,
-		categories: categoryList
+		categories: categoryList,
+		invoices: invoiceList
 	};
 };
 
@@ -122,6 +146,7 @@ export const actions: Actions = {
 		const projectId = fd.get('projectId')?.toString().trim() || null;
 		const categoryId = fd.get('categoryId')?.toString().trim() || null;
 		const accountId = fd.get('accountId')?.toString().trim() || null;
+		const invoiceId = fd.get('invoiceId')?.toString().trim() || null;
 		const expenseDate = fd.get('expenseDate')?.toString().trim();
 		const description = fd.get('description')?.toString().trim() || null;
 
@@ -144,6 +169,7 @@ export const actions: Actions = {
 			projectId: resolvedProjectId,
 			categoryId: categoryId || null,
 			accountId: accountId || null,
+			invoiceId: invoiceId || null,
 			submittedBy: user.id,
 			title,
 			description,
@@ -322,6 +348,22 @@ export const actions: Actions = {
 			{ expenseId, accountId, previousAccountId: expense.accountId }
 		);
 
+		return { success: true };
+	},
+
+	linkInvoice: async ({ request, locals, params }) => {
+		await requireCompanyRoleAny(locals, params.companyId, ['admin', 'manager', 'accountant']);
+		const fd = await request.formData();
+		const expenseId = fd.get('expenseId')?.toString();
+		const invoiceId = fd.get('invoiceId')?.toString().trim() || null;
+
+		if (!expenseId) return fail(400, { error: 'Expense ID required' });
+
+		await db
+			.update(expenses)
+			.set({ invoiceId, updatedAt: new Date() })
+			.where(eq(expenses.id, expenseId));
+
 		return { success: true };
 	}
 };
diff --git a/src/routes/(app)/companies/[companyId]/expenses/+page.svelte b/src/routes/(app)/companies/[companyId]/expenses/+page.svelte
index 1589fe4..dc53156 100644
--- a/src/routes/(app)/companies/[companyId]/expenses/+page.svelte
+++ b/src/routes/(app)/companies/[companyId]/expenses/+page.svelte
@@ -88,6 +88,15 @@
 						{/each}
 					</select>
 				</div>
+				<div>
+					<label for="exp-invoice" class={labelCls}>Invoice</label>
+					<select id="exp-invoice" name="invoiceId" class={inputCls}>
+						<option value="">—</option>
+						{#each data.invoices as inv (inv.id)}
+							<option value={inv.id}>{inv.invoiceNumber} — {inv.partyName} ({inv.direction})</option>
+						{/each}
+					</select>
+				</div>
 				<div class="md:col-span-2">
 					<label for="exp-desc" class={labelCls}>Description</label>
 					<textarea id="exp-desc" name="description" rows="2" class={inputCls}></textarea>
@@ -150,6 +159,19 @@
 									</span>
 								</p>
 							{/if}
+							{#if expense.invoiceId}
+								{@const inv = data.invoices.find((i) => i.id === expense.invoiceId)}
+								{#if inv}
+									<p class="mt-1 text-xs">
+										<a
+											href={`/companies/${data.company.id}/invoices/${inv.id}`}
+											class="rounded-full bg-indigo-100 px-2 py-0.5 font-medium text-indigo-700 hover:bg-indigo-200 dark:bg-indigo-900/40 dark:text-indigo-300"
+										>
+											Invoice: {inv.invoiceNumber}
+										</a>
+									</p>
+								{/if}
+							{/if}
 						</div>
 						<div class="text-right">
 							<p class="text-lg font-semibold dark:text-white">{formatCurrency(expense.amount, expense.currency)}</p>