diff --git a/app_new/gmao_config/routes.py b/app_new/gmao_config/routes.py
index e286210..c695af8 100644
--- a/app_new/gmao_config/routes.py
+++ b/app_new/gmao_config/routes.py
@@ -8,6 +8,16 @@ from app_new.extensions import db
 from app_new.outlook.models import GmaoContext
 
 gmao_config_bp = Blueprint('gmao_config', __name__, template_folder='templates')
+LOOKBACK_MAX_HOURS = 24 * 365
+
+
+def _bounded_int(value, default, minimum=1, maximum=None):
+    try:
+        parsed = int(value)
+    except (TypeError, ValueError):
+        parsed = default
+    parsed = max(minimum, parsed)
+    return min(maximum, parsed) if maximum is not None else parsed
 
 
 @gmao_config_bp.route('/')
@@ -65,7 +75,10 @@ def save():
     context.auto_interpret_enabled = request.form.get('auto_interpret_enabled') == 'on'
     context.auto_interpret_interval = max(1, int(request.form.get('auto_interpret_interval', 10)))
     context.auto_interpret_max_emails = max(1, int(request.form.get('auto_interpret_max_emails', 5)))
-    context.auto_interpret_lookback_hours = max(1, int(request.form.get('auto_interpret_lookback_hours', 24)))
+    context.auto_interpret_lookback_hours = _bounded_int(
+        request.form.get('auto_interpret_lookback_hours'), 24,
+        maximum=LOOKBACK_MAX_HOURS,
+    )
     
     # Activation de la synchronisation PRONOTE
     context.pronote_sync_enabled = request.form.get('pronote_sync_enabled') == 'on'
@@ -75,7 +88,10 @@ def save():
     # Activation de la synchronisation Outlook
     context.outlook_sync_enabled = request.form.get('outlook_sync_enabled') == 'on'
     context.outlook_sync_interval = max(1, int(request.form.get('outlook_sync_interval', 10)))
-    context.outlook_sync_lookback_hours = max(1, int(request.form.get('outlook_sync_lookback_hours', 24)))
+    context.outlook_sync_lookback_hours = _bounded_int(
+        request.form.get('outlook_sync_lookback_hours'), 24,
+        maximum=LOOKBACK_MAX_HOURS,
+    )
     
     # Configuration IA
     from app_new.core.models.settings import AppSettings
diff --git a/app_new/gmao_config/templates/gmao_config/index.html b/app_new/gmao_config/templates/gmao_config/index.html
index f03b2ec..c779871 100644
--- a/app_new/gmao_config/templates/gmao_config/index.html
+++ b/app_new/gmao_config/templates/gmao_config/index.html
@@ -249,9 +249,10 @@
                                        value="{{ context.auto_interpret_max_emails or 5 }}">
                             </div>
                             <div class="col-md-4 mb-3">
-                                <label class="form-label">Lookback (heures)</label>
-                                <input type="number" name="auto_interpret_lookback_hours" class="form-control" min="1" max="168"
+                                <label class="form-label">Lookback ENT / interprétation (heures)</label>
+                                <input type="number" name="auto_interpret_lookback_hours" class="form-control" min="1" max="8760"
                                        value="{{ context.auto_interpret_lookback_hours or 24 }}">
+                                <small class="text-muted">Maximum : 8 760 heures (365 jours).</small>
                             </div>
                         </div>
                     </div>
@@ -306,8 +307,9 @@
                             </div>
                             <div class="col-md-6 mb-3">
                                 <label class="form-label">Lookback (heures)</label>
-                                <input type="number" name="outlook_sync_lookback_hours" class="form-control" min="1" max="168"
+                                <input type="number" name="outlook_sync_lookback_hours" class="form-control" min="1" max="8760"
                                        value="{{ context.outlook_sync_lookback_hours or 24 }}">
+                                <small class="text-muted">Maximum : 8 760 heures (365 jours).</small>
                             </div>
                         </div>
                     </div>
@@ -415,4 +417,4 @@ function testInterpretation() {
     });
 }
 </script>
-{% endblock %}
\ No newline at end of file
+{% endblock %}
diff --git a/app_new/templates/gmao_config/index.html b/app_new/templates/gmao_config/index.html
index f03b2ec..c779871 100644
--- a/app_new/templates/gmao_config/index.html
+++ b/app_new/templates/gmao_config/index.html
@@ -249,9 +249,10 @@
                                        value="{{ context.auto_interpret_max_emails or 5 }}">
                             </div>
                             <div class="col-md-4 mb-3">
-                                <label class="form-label">Lookback (heures)</label>
-                                <input type="number" name="auto_interpret_lookback_hours" class="form-control" min="1" max="168"
+                                <label class="form-label">Lookback ENT / interprétation (heures)</label>
+                                <input type="number" name="auto_interpret_lookback_hours" class="form-control" min="1" max="8760"
                                        value="{{ context.auto_interpret_lookback_hours or 24 }}">
+                                <small class="text-muted">Maximum : 8 760 heures (365 jours).</small>
                             </div>
                         </div>
                     </div>
@@ -306,8 +307,9 @@
                             </div>
                             <div class="col-md-6 mb-3">
                                 <label class="form-label">Lookback (heures)</label>
-                                <input type="number" name="outlook_sync_lookback_hours" class="form-control" min="1" max="168"
+                                <input type="number" name="outlook_sync_lookback_hours" class="form-control" min="1" max="8760"
                                        value="{{ context.outlook_sync_lookback_hours or 24 }}">
+                                <small class="text-muted">Maximum : 8 760 heures (365 jours).</small>
                             </div>
                         </div>
                     </div>
@@ -415,4 +417,4 @@ function testInterpretation() {
     });
 }
 </script>
-{% endblock %}
\ No newline at end of file
+{% endblock %}
diff --git a/tests/integration/test_gmao_config_lookback.py b/tests/integration/test_gmao_config_lookback.py
new file mode 100644
index 0000000..04d1b72
--- /dev/null
+++ b/tests/integration/test_gmao_config_lookback.py
@@ -0,0 +1,30 @@
+from app_new.extensions import db
+from app_new.outlook.models import GmaoContext
+
+
+def test_gmao_config_accepts_one_year_lookback(authenticated_client, app, admin_user):
+    response = authenticated_client.post('/gmao-config/save', data={
+        'auto_interpret_lookback_hours': '8760',
+        'outlook_sync_lookback_hours': '8760',
+    })
+    assert response.status_code == 302
+    with app.app_context():
+        context = GmaoContext.query.filter_by(user_id=admin_user['id']).one()
+        assert context.auto_interpret_lookback_hours == 8760
+        assert context.outlook_sync_lookback_hours == 8760
+        db.session.delete(context)
+        db.session.commit()
+
+
+def test_gmao_config_caps_lookback_at_one_year(authenticated_client, app, admin_user):
+    response = authenticated_client.post('/gmao-config/save', data={
+        'auto_interpret_lookback_hours': '9000',
+        'outlook_sync_lookback_hours': '9000',
+    })
+    assert response.status_code == 302
+    with app.app_context():
+        context = GmaoContext.query.filter_by(user_id=admin_user['id']).one()
+        assert context.auto_interpret_lookback_hours == 8760
+        assert context.outlook_sync_lookback_hours == 8760
+        db.session.delete(context)
+        db.session.commit()