diff --git a/app/Service/LocalizationService.php b/app/Service/LocalizationService.php
index bee7490a..7d145f41 100644
--- a/app/Service/LocalizationService.php
+++ b/app/Service/LocalizationService.php
@@ -155,14 +155,9 @@ class LocalizationService
     }
 
     /**
-     * Time group types have no server-side descriptor, so reports fall back to rendering the raw
-     * aggregation key. For the Day type that key is an ISO date (Y-m-d), which is formatted here
-     * so exports match the rest of the UI instead of leaking the key.
-     *
-     * Week, month and year keys have different shapes ('Y-m-d' for the week start, 'Y-m' and 'Y'),
-     * and are not offered as a grouping in the reporting UI, so they are returned unchanged.
-     * Presenting those needs its own decision: a week rendered as its start date reads as a single
-     * day, and a month rendered with a full date format reads as a specific day.
+     * Time group types have no server-side descriptor; Day and Week keys are ISO dates and
+     * formatted here instead. A Week key is the first day of that week, so it renders as the
+     * range it covers.
      */
     public function formatTimeGroupKey(?string $key, TimeEntryAggregationType $groupType): ?string
     {
@@ -170,11 +165,17 @@ class LocalizationService
             return null;
         }
 
-        if ($groupType !== TimeEntryAggregationType::Day) {
-            return $key;
+        if ($groupType === TimeEntryAggregationType::Day) {
+            return $this->formatDate(Carbon::parse($key));
         }
 
-        return $this->formatDate(Carbon::parse($key));
+        if ($groupType === TimeEntryAggregationType::Week) {
+            $weekStart = Carbon::parse($key);
+
+            return $this->formatDate($weekStart).' - '.$this->formatDate($weekStart->copy()->addDays(6));
+        }
+
+        return $key;
     }
 
     public function setDateFormat(DateFormat $dateFormat): void
diff --git a/e2e/reporting.spec.ts b/e2e/reporting.spec.ts
index 1c855dbd..f19ded9e 100644
--- a/e2e/reporting.spec.ts
+++ b/e2e/reporting.spec.ts
@@ -10,6 +10,7 @@ import {
     createTimeEntryWithTagViaApi,
     createTimeEntryWithBillableStatusViaApi,
     createBareTimeEntryViaApi,
+    createTimeEntryOnDateViaApi,
     createPublicProjectViaApi,
     updateOrganizationSettingViaApi,
 } from './utils/api';
@@ -885,6 +886,83 @@ test('test that group by date groups the report by day and formats the date labe
     );
 });
 
+test('test that group by week requests week grouping and does not leak the raw group key', async ({
+    page,
+    ctx,
+}) => {
+    await createTimeEntryViaApi(ctx, {
+        description: 'Entry for group by week',
+        duration: '1h',
+    });
+
+    await goToReporting(page);
+    await expect(page.getByRole('button', { name: 'Export' })).toBeVisible();
+
+    const groupBySelects = page.locator('[data-testid="reporting_view"]').getByRole('combobox');
+    await groupBySelects.filter({ hasText: 'Project' }).first().click();
+
+    const [aggregateResponse] = await Promise.all([
+        page.waitForResponse(
+            (response) =>
+                response.url().includes('/time-entries/aggregate') &&
+                response.url().includes('group=week') &&
+                response.status() === 200
+        ),
+        page.getByRole('option', { name: 'Week', exact: true }).click(),
+    ]);
+
+    const requestUrl = new URL(aggregateResponse.url());
+    expect(requestUrl.searchParams.get('group')).toBe('week');
+
+    // The raw group key is the first day of the week and must not leak through.
+    await expect(page.getByTestId('reporting_view').getByText(/^\d{4}-\d{2}-\d{2}$/)).toHaveCount(
+        0
+    );
+});
+
+test('test that group by week labels a week spanning new year with a range crossing the year', async ({
+    page,
+    ctx,
+}) => {
+    await updateOrganizationSettingViaApi(ctx, { date_format: 'slash-separated-dd-mm-yyyy' });
+
+    for (const day of ['2025-12-22', '2025-12-29', '2026-01-05']) {
+        await createTimeEntryOnDateViaApi(ctx, {
+            date: new Date(`${day}T09:00:00Z`),
+            duration: '1h',
+            description: `Entry for ${day}`,
+        });
+    }
+
+    // The reporting page keeps its range in session storage, so seed a range spanning new year
+    // rather than driving the date picker.
+    await page.addInitScript(() => {
+        window.sessionStorage.setItem('reporting-start-date', '2025-12-15');
+        window.sessionStorage.setItem('reporting-end-date', '2026-01-15');
+    });
+
+    await goToReporting(page);
+    await expect(page.getByRole('button', { name: 'Export' })).toBeVisible();
+
+    const groupBySelects = page.locator('[data-testid="reporting_view"]').getByRole('combobox');
+    await groupBySelects.filter({ hasText: 'Project' }).first().click();
+    await Promise.all([
+        page.waitForResponse(
+            (response) =>
+                response.url().includes('/time-entries/aggregate') &&
+                response.url().includes('group=week') &&
+                response.status() === 200
+        ),
+        page.getByRole('option', { name: 'Week', exact: true }).click(),
+    ]);
+
+    const reportingView = page.getByTestId('reporting_view');
+    await expect(reportingView.getByText('22/12/2025 - 28/12/2025', { exact: true })).toBeVisible();
+    await expect(reportingView.getByText('29/12/2025 - 04/01/2026', { exact: true })).toBeVisible();
+    await expect(reportingView.getByText('05/01/2026 - 11/01/2026', { exact: true })).toBeVisible();
+    await expect(reportingView.getByText(/^\d{4}-\d{2}-\d{2}$/)).toHaveCount(0);
+});
+
 // ──────────────────────────────────────────────────
 // Export Tests
 // ──────────────────────────────────────────────────
diff --git a/resources/js/packages/ui/src/utils/time.test.ts b/resources/js/packages/ui/src/utils/time.test.ts
index 35a873a9..8c9923c7 100644
--- a/resources/js/packages/ui/src/utils/time.test.ts
+++ b/resources/js/packages/ui/src/utils/time.test.ts
@@ -1,5 +1,5 @@
 import { describe, expect, test } from 'vitest';
-import { formatHumanReadableDuration, formatReportingDuration } from './time';
+import { formatHumanReadableDuration, formatReportingDuration, formatWeekRange } from './time';
 
 const seconds = 14 * 3600 + 45 * 60 + 6; // 14h 45m 06s
 
@@ -42,3 +42,21 @@ describe('formatReportingDuration', () => {
         );
     });
 });
+
+describe('formatWeekRange', () => {
+    test('renders the six days following the given first day of the week', () => {
+        expect(formatWeekRange('2026-07-27', 'slash-separated-dd-mm-yyyy')).toBe(
+            '27/07/2026 - 02/08/2026'
+        );
+    });
+
+    test('spans a month boundary', () => {
+        expect(formatWeekRange('2026-07-27')).toBe('27.7.2026 - 2.8.2026');
+    });
+
+    test('spans a year boundary', () => {
+        expect(formatWeekRange('2025-12-29', 'slash-separated-dd-mm-yyyy')).toBe(
+            '29/12/2025 - 04/01/2026'
+        );
+    });
+});
diff --git a/resources/js/packages/ui/src/utils/time.ts b/resources/js/packages/ui/src/utils/time.ts
index 4031f2fe..7a7a93be 100644
--- a/resources/js/packages/ui/src/utils/time.ts
+++ b/resources/js/packages/ui/src/utils/time.ts
@@ -236,6 +236,15 @@ export function formatWeek(date: string | null): string {
     return 'Week ' + getDayJsInstance()(date).week();
 }
 
+/*
+ * Returns the range covered by the week starting on the given day.
+ * @param date - first day of a week, in the format of 'YYYY-MM-DD'
+ */
+export function formatWeekRange(date: string, format?: DateFormat): string {
+    const end = getDayJsInstance()(date).add(6, 'day').format('YYYY-MM-DD');
+    return `${formatDate(date, format)} - ${formatDate(end, format)}`;
+}
+
 /*
  * Returns a human readable date format.
  * @param date - date in the format of 'YYYY-MM-DD'
diff --git a/resources/js/utils/useReporting.ts b/resources/js/utils/useReporting.ts
index fccceec2..8e0181ef 100644
--- a/resources/js/utils/useReporting.ts
+++ b/resources/js/utils/useReporting.ts
@@ -7,10 +7,15 @@ import { useTasksQuery } from '@/utils/useTasksQuery';
 import { useClientsQuery } from '@/utils/useClientsQuery';
 import { useTagsQuery } from '@/utils/useTagsQuery';
 import { CheckCircleIcon, UserCircleIcon, UserGroupIcon } from '@heroicons/vue/20/solid';
-import { CalendarIcon, DocumentTextIcon, FolderIcon } from '@heroicons/vue/16/solid';
+import {
+    CalendarDaysIcon,
+    CalendarIcon,
+    DocumentTextIcon,
+    FolderIcon,
+} from '@heroicons/vue/16/solid';
 import { Coffee } from '@lucide/vue';
 import BillableIcon from '@/packages/ui/src/Icons/BillableIcon.vue';
-import { type DateFormat, formatDate } from '@/packages/ui/src/utils/time';
+import { type DateFormat, formatDate, formatWeekRange } from '@/packages/ui/src/utils/time';
 
 export type GroupingOption =
     | 'project'
@@ -21,7 +26,8 @@ export type GroupingOption =
     | 'description'
     | 'tag'
     | 'type'
-    | 'day';
+    | 'day'
+    | 'week';
 
 export const useReportingStore = defineStore('reporting', () => {
     // Cache query composables to avoid creating new subscriptions on every call
@@ -85,6 +91,9 @@ export const useReportingStore = defineStore('reporting', () => {
         if (type === 'day') {
             return formatDate(key, dateFormat);
         }
+        if (type === 'week') {
+            return formatWeekRange(key, dateFormat);
+        }
         return key;
     }
 
@@ -138,6 +147,11 @@ export const useReportingStore = defineStore('reporting', () => {
             value: 'day',
             icon: CalendarIcon,
         },
+        {
+            label: 'Week',
+            value: 'week',
+            icon: CalendarDaysIcon,
+        },
     ];
 
     return {
diff --git a/tests/Unit/Endpoint/Api/V1/TimeEntryEndpointTest.php b/tests/Unit/Endpoint/Api/V1/TimeEntryEndpointTest.php
index a6eff697..0ba74fff 100644
--- a/tests/Unit/Endpoint/Api/V1/TimeEntryEndpointTest.php
+++ b/tests/Unit/Endpoint/Api/V1/TimeEntryEndpointTest.php
@@ -17,6 +17,7 @@ use App\Jobs\RecalculateSpentTimeForProject;
 use App\Jobs\RecalculateSpentTimeForTask;
 use App\Models\Client;
 use App\Models\Member;
+use App\Models\Organization;
 use App\Models\Project;
 use App\Models\Tag;
 use App\Models\Task;
@@ -1742,6 +1743,112 @@ class TimeEntryEndpointTest extends ApiEndpointTestAbstract
         $this->assertStringNotContainsString('2024-03-14', $csv);
     }
 
+    /**
+     * @return array{0: Organization, 1: Member, 2: User}
+     */
+    private function createWeeksSpanningNewYear(): array
+    {
+        $data = $this->createUserWithPermission([
+            'time-entries:view:all',
+        ]);
+        // Note: the organization factory randomizes the date format, so pin it
+        $data->organization->update(['date_format' => DateFormat::SlashSeparatedDDMMYYYY]);
+        $project = Project::factory()->forOrganization($data->organization)->create();
+        // Note: the user factory pins the week start to Monday, so these land in predictable buckets
+        foreach (['2025-12-22', '2025-12-29', '2026-01-05'] as $day) {
+            TimeEntry::factory()->forOrganization($data->organization)->forProject($project)->forMember($data->member)
+                ->startWithDuration(Carbon::parse($day.' 09:00:00', 'UTC'), 3600)->create();
+        }
+
+        return [$data->organization, $data->member, $data->user];
+    }
+
+    public function test_aggregate_export_csv_labels_a_week_group_with_its_date_range(): void
+    {
+        // Arrange
+        $this->travelTo(Carbon::create(2026, 1, 15, 12, 0, 0, 'UTC'));
+        [$organization, , $user] = $this->createWeeksSpanningNewYear();
+        Passport::actingAs($user);
+
+        // Act
+        $response = $this->getJson(route('api.v1.time-entries.aggregate-export', [
+            $organization->getKey(),
+            'format' => ExportFormat::CSV,
+            'group' => TimeEntryAggregationType::Week,
+            'sub_group' => TimeEntryAggregationType::Project,
+            'history_group' => TimeEntryAggregationTypeInterval::Week,
+            'start' => Carbon::parse('2025-12-15 00:00:00', 'UTC')->toIso8601ZuluString(),
+            'end' => Carbon::parse('2026-01-15 23:59:59', 'UTC')->toIso8601ZuluString(),
+        ]));
+
+        // Assert
+        $this->assertResponseCode($response, 200);
+        $disk = Storage::disk(config('filesystems.private'));
+        $files = $disk->files('exports');
+        $this->assertCount(1, $files);
+        $csv = $disk->get($files[0]);
+        $this->assertIsString($csv);
+        $this->assertStringContainsString('22/12/2025 - 28/12/2025', $csv);
+        $this->assertStringContainsString('29/12/2025 - 04/01/2026', $csv);
+        $this->assertStringContainsString('05/01/2026 - 11/01/2026', $csv);
+        $this->assertStringNotContainsString('2025-12-29', $csv);
+        $this->assertStringNotContainsString('2025-12-22', $csv);
+    }
+
+    public function test_aggregate_export_endpoints_can_create_a_pdf_report_grouped_by_week_spanning_new_year(): void
+    {
+        // Arrange
+        $this->travelTo(Carbon::create(2026, 1, 15, 12, 0, 0, 'UTC'));
+        [$organization, , $user] = $this->createWeeksSpanningNewYear();
+        Passport::actingAs($user);
+        $this->actAsOrganizationWithSubscription();
+
+        // Act
+        // Note: a week 1 label carries a comma and reaches the echarts series in a <script> tag
+        $response = $this->getJson(route('api.v1.time-entries.aggregate-export', [
+            $organization->getKey(),
+            'format' => ExportFormat::PDF,
+            'group' => TimeEntryAggregationType::Week,
+            'sub_group' => TimeEntryAggregationType::Project,
+            'history_group' => TimeEntryAggregationTypeInterval::Week,
+            'start' => Carbon::parse('2025-12-15 00:00:00', 'UTC')->toIso8601ZuluString(),
+            'end' => Carbon::parse('2026-01-15 23:59:59', 'UTC')->toIso8601ZuluString(),
+        ]));
+
+        // Assert
+        $this->assertResponseCode($response, 200);
+    }
+
+    public function test_aggregate_export_pdf_labels_a_week_group_with_its_date_range(): void
+    {
+        // Arrange
+        $this->travelTo(Carbon::create(2026, 1, 15, 12, 0, 0, 'UTC'));
+        [$organization, , $user] = $this->createWeeksSpanningNewYear();
+        Passport::actingAs($user);
+        $this->actAsOrganizationWithSubscription();
+
+        // Act
+        // Note: debug=true returns the rendered HTML instead of handing it to the PDF renderer.
+        $response = $this->getJson(route('api.v1.time-entries.aggregate-export', [
+            $organization->getKey(),
+            'format' => ExportFormat::PDF,
+            'group' => TimeEntryAggregationType::Week,
+            'sub_group' => TimeEntryAggregationType::Project,
+            'history_group' => TimeEntryAggregationTypeInterval::Week,
+            'start' => Carbon::parse('2025-12-15 00:00:00', 'UTC')->toIso8601ZuluString(),
+            'end' => Carbon::parse('2026-01-15 23:59:59', 'UTC')->toIso8601ZuluString(),
+            'debug' => 'true',
+        ]));
+
+        // Assert
+        $this->assertResponseCode($response, 200);
+        $html = $response->json('html');
+        $this->assertIsString($html);
+        $this->assertStringContainsString('22/12/2025 - 28/12/2025', $html);
+        $this->assertStringContainsString('29/12/2025 - 04/01/2026', $html);
+        $this->assertStringNotContainsString('2025-12-29', $html);
+    }
+
     public function test_index_export_endpoint_with_client_ids_filter_returns_filtered_entries(): void
     {
         // Arrange
diff --git a/tests/Unit/Service/LocalizationServiceTest.php b/tests/Unit/Service/LocalizationServiceTest.php
index ea601fba..c1e3bf9d 100644
--- a/tests/Unit/Service/LocalizationServiceTest.php
+++ b/tests/Unit/Service/LocalizationServiceTest.php
@@ -326,15 +326,50 @@ class LocalizationServiceTest extends TestCaseWithDatabase
         $this->assertNull($formatted);
     }
 
-    public function test_format_time_group_key_returns_the_key_unchanged_for_non_day_group_types(): void
+    public function test_format_time_group_key_formats_a_week_key_as_the_range_it_covers(): void
+    {
+        // Arrange
+        $this->localizationService->setDateFormat(DateFormat::SlashSeparatedDDMMYYYY);
+
+        // Act
+        $formatted = $this->localizationService->formatTimeGroupKey('2026-07-27', TimeEntryAggregationType::Week);
+
+        // Assert
+        $this->assertSame('27/07/2026 - 02/08/2026', $formatted);
+    }
+
+    public function test_format_time_group_key_formats_a_week_range_from_the_weekday_of_its_own_key(): void
+    {
+        // Arrange
+        $this->localizationService->setDateFormat(DateFormat::SlashSeparatedDDMMYYYY);
+
+        // Act
+        $sundayStart = $this->localizationService->formatTimeGroupKey('2026-07-26', TimeEntryAggregationType::Week);
+        $mondayStart = $this->localizationService->formatTimeGroupKey('2026-07-20', TimeEntryAggregationType::Week);
+
+        // Assert
+        $this->assertSame('26/07/2026 - 01/08/2026', $sundayStart);
+        $this->assertSame('20/07/2026 - 26/07/2026', $mondayStart);
+    }
+
+    public function test_format_time_group_key_formats_a_week_range_spanning_new_year(): void
+    {
+        // Arrange
+        $this->localizationService->setDateFormat(DateFormat::SlashSeparatedDDMMYYYY);
+
+        // Act
+        $formatted = $this->localizationService->formatTimeGroupKey('2025-12-29', TimeEntryAggregationType::Week);
+
+        // Assert
+        $this->assertSame('29/12/2025 - 04/01/2026', $formatted);
+    }
+
+    public function test_format_time_group_key_does_not_change_month_year_and_entity_group_types(): void
     {
         // Arrange
         $this->localizationService->setDateFormat(DateFormat::SlashSeparatedDDMMYYYY);
 
         // Act & Assert
-        // Week/month/year are not offered as a grouping in the reporting UI and their keys have
-        // different shapes, so they are passed through rather than formatted as a date.
-        $this->assertSame('2001-02-03', $this->localizationService->formatTimeGroupKey('2001-02-03', TimeEntryAggregationType::Week));
         $this->assertSame('2001-02', $this->localizationService->formatTimeGroupKey('2001-02', TimeEntryAggregationType::Month));
         $this->assertSame('2001', $this->localizationService->formatTimeGroupKey('2001', TimeEntryAggregationType::Year));
         $this->assertSame('some-uuid', $this->localizationService->formatTimeGroupKey('some-uuid', TimeEntryAggregationType::Project));
diff --git a/tests/Unit/Service/TimeEntryAggregationServiceTest.php b/tests/Unit/Service/TimeEntryAggregationServiceTest.php
index 83bb6e3d..e00f8005 100644
--- a/tests/Unit/Service/TimeEntryAggregationServiceTest.php
+++ b/tests/Unit/Service/TimeEntryAggregationServiceTest.php
@@ -1302,4 +1302,111 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
             ],
         ], $result);
     }
+
+    public function test_aggregate_time_entries_by_week_keys_each_group_by_the_first_day_of_the_week(): void
+    {
+        // Arrange
+        // 2026-07-20 is a Monday, 2026-07-26 is the Sunday of that week.
+        foreach (['2026-07-20', '2026-07-26', '2026-07-27'] as $day) {
+            TimeEntry::factory()->startWithDuration(Carbon::parse($day.' 09:00:00', 'UTC'), 10)->create();
+        }
+        $query = TimeEntry::query();
+
+        // Act
+        $result = $this->service->getAggregatedTimeEntries(
+            $query,
+            TimeEntryAggregationType::Week,
+            null,
+            'UTC',
+            Weekday::Monday,
+            false,
+            null,
+            null,
+            true,
+            null,
+            null
+        );
+
+        // Assert
+        $this->assertSame([
+            'seconds' => 30,
+            'cost' => 0,
+            'grouped_type' => 'week',
+            'grouped_data' => [
+                [
+                    'key' => '2026-07-20',
+                    'seconds' => 20,
+                    'cost' => 0,
+                    'grouped_type' => null,
+                    'grouped_data' => null,
+                ],
+                [
+                    'key' => '2026-07-27',
+                    'seconds' => 10,
+                    'cost' => 0,
+                    'grouped_type' => null,
+                    'grouped_data' => null,
+                ],
+            ],
+        ], $result);
+    }
+
+    public function test_aggregate_time_entries_by_week_aligns_the_group_key_to_the_organization_week_start(): void
+    {
+        // Arrange
+        // With a Sunday week start the Sunday entry belongs to the following week instead.
+        foreach (['2026-07-20', '2026-07-26', '2026-07-27'] as $day) {
+            TimeEntry::factory()->startWithDuration(Carbon::parse($day.' 09:00:00', 'UTC'), 10)->create();
+        }
+        $query = TimeEntry::query();
+
+        // Act
+        $result = $this->service->getAggregatedTimeEntries(
+            $query,
+            TimeEntryAggregationType::Week,
+            null,
+            'UTC',
+            Weekday::Sunday,
+            false,
+            null,
+            null,
+            true,
+            null,
+            null
+        );
+
+        // Assert
+        $this->assertSame(['2026-07-19', '2026-07-26'], array_column($result['grouped_data'], 'key'));
+        $this->assertSame([10, 20], array_column($result['grouped_data'], 'seconds'));
+    }
+
+    public function test_aggregate_time_entries_by_week_keys_a_week_spanning_new_year_by_its_start_in_the_earlier_year(): void
+    {
+        // Arrange
+        // Note: 2025-12-29 is the Monday of the week containing 1 January 2026
+        foreach (['2025-12-29', '2025-12-31', '2026-01-01', '2026-01-05'] as $day) {
+            TimeEntry::factory()->startWithDuration(Carbon::parse($day.' 09:00:00', 'UTC'), 10)->create();
+        }
+        $query = TimeEntry::query();
+
+        // Act
+        $result = $this->service->getAggregatedTimeEntries(
+            $query,
+            TimeEntryAggregationType::Week,
+            null,
+            'UTC',
+            Weekday::Monday,
+            false,
+            null,
+            null,
+            true,
+            null,
+            null
+        );
+
+        // Assert
+        $this->assertSame(['2025-12-29', '2026-01-05'], array_column($result['grouped_data'], 'key'));
+        // Three of the four entries fall in the week that straddles new year.
+        $this->assertSame([30, 10], array_column($result['grouped_data'], 'seconds'));
+    }
 }