diff --git a/lib/data/api/api_repository.dart b/lib/data/api/api_repository.dart
index bdd7ad5..8dade9d 100644
--- a/lib/data/api/api_repository.dart
+++ b/lib/data/api/api_repository.dart
@@ -57,6 +57,18 @@ class ApiRepository implements IeoseoRepository {
   @override
   Future<void> deleteEvent(String id) => _client.delete('/events/$id');
 
+  @override
+  Future<DkEvent> completeEvent(String id) async {
+    final dynamic data = await _client.post('/events/$id/complete');
+    return DkEventDto.fromJson(_asMap(data));
+  }
+
+  @override
+  Future<DkEvent> reopenEvent(String id) async {
+    final dynamic data = await _client.post('/events/$id/reopen');
+    return DkEventDto.fromJson(_asMap(data));
+  }
+
   // ── Tasks ───────────────────────────────────────────────
   @override
   Future<List<DkTask>> tasks({String? date}) async {
diff --git a/lib/data/api/dtos.dart b/lib/data/api/dtos.dart
index ab3e6d1..b482d16 100644
--- a/lib/data/api/dtos.dart
+++ b/lib/data/api/dtos.dart
@@ -68,6 +68,7 @@ abstract final class DkEventDto {
     pinned: json['pinned'] == true,
     memo: _str(json['memo']) ?? '',
     color: _str(json['color']) ?? 'cool',
+    completed: json['completed'] == true,
   );
 
   /// [DkEvent] → 생성 요청 본문(EventCreateRequest). id/파생계산은 보내지 않는다.
diff --git a/lib/data/data_controller.dart b/lib/data/data_controller.dart
index df3d9fb..e77b7a8 100644
--- a/lib/data/data_controller.dart
+++ b/lib/data/data_controller.dart
@@ -147,6 +147,35 @@ class DataController extends ChangeNotifier {
     }
   }
 
+  /// 이벤트 종료(완료) 처리. 자동 삭제 대신 유저 명시 액션(FRD 5.1).
+  Future<DkEvent> completeEvent(String id) => _setEventCompleted(id, true);
+
+  /// 종료 취소(재개).
+  Future<DkEvent> reopenEvent(String id) => _setEventCompleted(id, false);
+
+  Future<DkEvent> _setEventCompleted(String id, bool completed) async {
+    final List<DkEvent> snapshot = _events;
+    // 낙관적 업데이트 후 server 응답으로 교체, 실패 시 롤백.
+    _events = _events
+        .map((DkEvent e) => e.id == id ? e.copyWith(completed: completed) : e)
+        .toList();
+    notifyListeners();
+    try {
+      final DkEvent updated = completed
+          ? await _repo.completeEvent(id)
+          : await _repo.reopenEvent(id);
+      _events = _events
+          .map((DkEvent e) => e.id == updated.id ? updated : e)
+          .toList();
+      notifyListeners();
+      return updated;
+    } on Exception {
+      _events = snapshot;
+      notifyListeners();
+      rethrow;
+    }
+  }
+
   // ── Debts ───────────────────────────────────────────────
 
   Future<DkDebt> carryDebt(String id, {required String toDate}) async {
diff --git a/lib/data/models.dart b/lib/data/models.dart
index 5e395fa..9303eb6 100644
--- a/lib/data/models.dart
+++ b/lib/data/models.dart
@@ -186,6 +186,7 @@ class DkEvent {
     this.memo = '',
     this.color = 'cool',
     this.remindDays = const <int>[],
+    this.completed = false,
   });
 
   final String id;
@@ -209,6 +210,10 @@ class DkEvent {
   final String color;
   final List<int> remindDays;
 
+  /// 종료(완료) 처리 여부. true 면 홈 "다가오는 일정"에서 숨긴다(server `completed`).
+  /// 마감/기간이 지나도 자동 삭제하지 않고, 유저가 명시적으로 종료할 때만 true.
+  final bool completed;
+
   /// nullable 날짜 필드(date/start/end)는 센티넬([_unset])로 받아 **null 로 비우기**도
   /// 가능하게 한다(`field ?? this.field` 패턴은 null 설정을 못 함). 예: T1↔T2 전환 시 date 비우기.
   DkEvent copyWith({
@@ -223,6 +228,7 @@ class DkEvent {
     String? memo,
     String? color,
     List<int>? remindDays,
+    bool? completed,
   }) {
     return DkEvent(
       id: id ?? this.id,
@@ -236,6 +242,7 @@ class DkEvent {
       memo: memo ?? this.memo,
       color: color ?? this.color,
       remindDays: remindDays ?? this.remindDays,
+      completed: completed ?? this.completed,
     );
   }
 }
diff --git a/lib/data/repository.dart b/lib/data/repository.dart
index 62f47e8..cbcc0c4 100644
--- a/lib/data/repository.dart
+++ b/lib/data/repository.dart
@@ -23,6 +23,13 @@ abstract class IeoseoRepository {
   /// 이벤트 삭제(server: DELETE /events/{id} → 204).
   Future<void> deleteEvent(String id);
 
+  /// 종료(완료) 처리(server: POST /events/{id}/complete). 갱신된 이벤트 반환.
+  /// 마감/기간이 지나도 자동 삭제하지 않고, 유저가 명시적으로 종료할 때 호출.
+  Future<DkEvent> completeEvent(String id);
+
+  /// 종료 취소(재개, server: POST /events/{id}/reopen).
+  Future<DkEvent> reopenEvent(String id);
+
   // ── Tasks ───────────────────────────────────────────────
   /// 태스크 목록(server: GET /tasks). [date] 지정 시 해당 일자만.
   Future<List<DkTask>> tasks({String? date});
@@ -141,6 +148,20 @@ class MockRepository implements IeoseoRepository {
     _events = _events.where((DkEvent e) => e.id != id).toList();
   }
 
+  @override
+  Future<DkEvent> completeEvent(String id) async => _setCompleted(id, true);
+
+  @override
+  Future<DkEvent> reopenEvent(String id) async => _setCompleted(id, false);
+
+  DkEvent _setCompleted(String id, bool completed) {
+    final DkEvent updated = _events
+        .firstWhere((DkEvent e) => e.id == id)
+        .copyWith(completed: completed);
+    _events = _events.map((DkEvent e) => e.id == id ? updated : e).toList();
+    return updated;
+  }
+
   @override
   Future<List<DkTask>> tasks({String? date}) async {
     final Iterable<DkTask> all = date == null
diff --git a/lib/screens/main_scaffold.dart b/lib/screens/main_scaffold.dart
index e594349..e328583 100644
--- a/lib/screens/main_scaffold.dart
+++ b/lib/screens/main_scaffold.dart
@@ -310,6 +310,19 @@ class _MainScaffoldState extends State<MainScaffold>
       ),
       onSubmit: (DkEvent draft) =>
           _run(() => _c.updateEvent(draft), success: '이벤트를 저장했어요'),
+      onComplete: (DkEvent e) => e.completed
+          ? _run(
+              () => _c.reopenEvent(e.id),
+              success: '종료를 취소했어요',
+              successIcon: 'repeat',
+              successTone: DkTone.info,
+            )
+          : _run(
+              () => _c.completeEvent(e.id),
+              success: '일정을 종료했어요',
+              successIcon: 'check',
+              successTone: DkTone.success,
+            ),
     );
   }
 
diff --git a/lib/screens/sheets/event_sheet.dart b/lib/screens/sheets/event_sheet.dart
index dd548b1..21f3a97 100644
--- a/lib/screens/sheets/event_sheet.dart
+++ b/lib/screens/sheets/event_sheet.dart
@@ -24,6 +24,7 @@ class EventSheetBody extends StatefulWidget {
     required this.onClose,
     this.onDelete,
     this.onSubmit,
+    this.onComplete,
   });
 
   final DkEvent? event;
@@ -34,6 +35,9 @@ class EventSheetBody extends StatefulWidget {
   /// 추가/저장 제출. 폼 값으로 만든 초안(신규는 id 빈 문자열)을 전달한다.
   final ValueChanged<DkEvent>? onSubmit;
 
+  /// 종료(완료) 토글. 현재 이벤트를 전달하면 호출부가 `completed` 에 따라 종료/재개한다.
+  final ValueChanged<DkEvent>? onComplete;
+
   @override
   State<EventSheetBody> createState() => _EventSheetBodyState();
 }
@@ -383,30 +387,66 @@ class _EventSheetBodyState extends State<EventSheetBody> {
   }
 
   Widget _stickyActions(DkTokens t, DkEvent? ev) {
-    return Row(
+    final bool isCompleted = ev?.completed ?? false;
+    return Column(
+      mainAxisSize: MainAxisSize.min,
       children: <Widget>[
-        if (!widget.isNew && ev != null) ...<Widget>[
-          DkButton(
-            size: DkButtonSize.lg,
-            variant: DkButtonVariant.danger,
-            onPressed: () {
-              widget.onDelete?.call(ev);
-              widget.onClose();
-            },
-            leading: DkIcon('trash', size: 18, color: t.danger, strokeWidth: 2),
+        // 종료(완료) 토글 — 기존 이벤트만. 자동 삭제 대신 유저가 명시적으로 종료(FRD 5.1).
+        if (!widget.isNew &&
+            ev != null &&
+            widget.onComplete != null) ...<Widget>[
+          SizedBox(
+            width: double.infinity,
+            child: DkButton(
+              size: DkButtonSize.lg,
+              full: true,
+              variant: DkButtonVariant.outline,
+              onPressed: () {
+                widget.onComplete!.call(ev);
+                widget.onClose();
+              },
+              leading: DkIcon(
+                isCompleted ? 'repeat' : 'check',
+                size: 18,
+                color: t.fg,
+                strokeWidth: 2,
+              ),
+              child: Text(isCompleted ? '종료 취소' : '종료 처리'),
+            ),
           ),
-          const SizedBox(width: 10),
+          const SizedBox(height: 10),
         ],
-        Expanded(
-          child: DkButton(
-            size: DkButtonSize.lg,
-            full: true,
-            onPressed: () {
-              widget.onSubmit?.call(_draft());
-              widget.onClose();
-            },
-            child: Text(widget.isNew ? '추가하기' : '저장'),
-          ),
+        Row(
+          children: <Widget>[
+            if (!widget.isNew && ev != null) ...<Widget>[
+              DkButton(
+                size: DkButtonSize.lg,
+                variant: DkButtonVariant.danger,
+                onPressed: () {
+                  widget.onDelete?.call(ev);
+                  widget.onClose();
+                },
+                leading: DkIcon(
+                  'trash',
+                  size: 18,
+                  color: t.danger,
+                  strokeWidth: 2,
+                ),
+              ),
+              const SizedBox(width: 10),
+            ],
+            Expanded(
+              child: DkButton(
+                size: DkButtonSize.lg,
+                full: true,
+                onPressed: () {
+                  widget.onSubmit?.call(_draft());
+                  widget.onClose();
+                },
+                child: Text(widget.isNew ? '추가하기' : '저장'),
+              ),
+            ),
+          ],
         ),
       ],
     );
@@ -420,6 +460,7 @@ Future<void> showEventSheet(
   required bool isNew,
   ValueChanged<DkEvent>? onDelete,
   ValueChanged<DkEvent>? onSubmit,
+  ValueChanged<DkEvent>? onComplete,
 }) {
   return showDkSheet<void>(
     context,
@@ -432,6 +473,7 @@ Future<void> showEventSheet(
         onClose: () => Navigator.of(sheetContext).maybePop(),
         onDelete: onDelete,
         onSubmit: onSubmit,
+        onComplete: onComplete,
       ),
     ),
   );
diff --git a/lib/screens/today/today_screen.dart b/lib/screens/today/today_screen.dart
index 9a3f5d8..889b363 100644
--- a/lib/screens/today/today_screen.dart
+++ b/lib/screens/today/today_screen.dart
@@ -45,7 +45,10 @@ class TodayScreen extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final List<DkEvent> ordered = ddayOrdered(events);
+    // 종료(완료) 처리한 이벤트는 홈에서 숨긴다(미종료는 D+ 로 계속 노출). FRD 5.1.
+    final List<DkEvent> ordered = ddayOrdered(
+      events.where((DkEvent e) => !e.completed).toList(growable: false),
+    );
     final int debtTotal = debts.fold(0, (int s, DkDebt d) => s + d.mins);
     final int debtOverdue = debts
         .where((DkDebt d) => d.status == DkDebtStatus.overdue)
diff --git a/test/data_controller_test.dart b/test/data_controller_test.dart
index 56573c8..ed7e6cd 100644
--- a/test/data_controller_test.dart
+++ b/test/data_controller_test.dart
@@ -128,6 +128,46 @@ void main() {
     });
   });
 
+  group('completeEvent / reopenEvent (종료 처리)', () {
+    const DkEvent e1 = DkEvent(
+      id: 'e1',
+      type: DkEventType.single,
+      title: '시험',
+      category: '자격증',
+      date: '2026-08-02',
+    );
+
+    test('종료 처리하면 completed=true 로 반영된다', () async {
+      final DataController c = DataController(
+        MockRepository(
+          tasks: <DkTask>[],
+          events: <DkEvent>[e1],
+          debts: <DkDebt>[],
+        ),
+      );
+      await c.load();
+
+      await c.completeEvent('e1');
+
+      expect(c.events.single.completed, isTrue);
+    });
+
+    test('종료 취소하면 completed=false 로 되돌린다', () async {
+      final DataController c = DataController(
+        MockRepository(
+          tasks: <DkTask>[],
+          events: <DkEvent>[e1.copyWith(completed: true)],
+          debts: <DkDebt>[],
+        ),
+      );
+      await c.load();
+
+      await c.reopenEvent('e1');
+
+      expect(c.events.single.completed, isFalse);
+    });
+  });
+
   group('autoCarryDebt (F6 낙관·롤백)', () {
     test('낙관적으로 assigned 표시 후 실패 시 원래 상태로 롤백한다', () async {
       final DataController c = DataController(_FailingAutoCarryRepo());
diff --git a/test/today_test.dart b/test/today_test.dart
index cbbdf72..95b2b40 100644
--- a/test/today_test.dart
+++ b/test/today_test.dart
@@ -69,4 +69,26 @@ void main() {
     await tester.tap(find.text('미룬 시간'));
     expect(opened, true);
   });
+
+  testWidgets('종료(완료) 처리한 이벤트는 홈에서 숨긴다', (WidgetTester tester) async {
+    const DkEvent done = DkEvent(
+      id: 'done',
+      type: DkEventType.single,
+      title: '끝난 일정',
+      category: '자격증',
+      date: '2026-12-01',
+      completed: true,
+    );
+    const DkEvent live = DkEvent(
+      id: 'live',
+      type: DkEventType.single,
+      title: '남은 일정',
+      category: '자격증',
+      date: '2026-12-02',
+    );
+    await _pumpTall(tester, _screen(events: <DkEvent>[done, live]));
+
+    expect(find.text('끝난 일정'), findsNothing);
+    expect(find.text('남은 일정'), findsOneWidget);
+  });
 }