diff --git a/components/calendar/calendar-agenda-view.tsx b/components/calendar/calendar-agenda-view.tsx
index 1aa0513c..a31510e8 100644
--- a/components/calendar/calendar-agenda-view.tsx
+++ b/components/calendar/calendar-agenda-view.tsx
@@ -148,6 +148,9 @@ export function CalendarAgendaView({
               const color = getEventColor(ev, calendar);
               const start = getEventStartDate(ev);
               const end = getEventEndDate(ev);
+              // iTIP CANCEL marks the attendee's copy with status "cancelled"
+              // instead of deleting it (#572).
+              const isCancelled = ev.status === "cancelled";
               const locationName = ev.locations
                 ? Object.values(ev.locations)[0]?.name
                 : null;
@@ -159,7 +162,10 @@ export function CalendarAgendaView({
                   onMouseEnter={(e) => onHoverEvent?.(ev, e.currentTarget.getBoundingClientRect())}
                   onMouseLeave={() => onHoverLeave?.()}
                   onContextMenu={onContextMenuEvent ? (e) => onContextMenuEvent(e, ev) : undefined}
-                  className="w-full flex items-start px-4 hover:bg-muted/50 transition-colors text-left"
+                  className={cn(
+                    "w-full flex items-start px-4 hover:bg-muted/50 transition-colors text-left",
+                    isCancelled && "opacity-60"
+                  )}
                   style={{ gap: 'var(--density-item-gap)', paddingBlock: 'var(--density-item-py)' }}
                 >
                   <div className="flex flex-col items-center pt-0.5 min-w-[60px]">
@@ -181,7 +187,7 @@ export function CalendarAgendaView({
                   />
 
                   <div className="flex-1 min-w-0">
-                    <div className="text-sm font-medium truncate">
+                    <div className={cn("text-sm font-medium truncate", isCancelled && "line-through")}>
                       {ev.title || t("events.no_title")}
                     </div>
                     {locationName && (
diff --git a/components/calendar/event-card.tsx b/components/calendar/event-card.tsx
index 10808d0e..33d9e484 100644
--- a/components/calendar/event-card.tsx
+++ b/components/calendar/event-card.tsx
@@ -88,7 +88,10 @@ export function EventCard({ event, calendar, variant, onClick, onMouseEnter, onM
     try { return format(d, fmt); } catch { return "--:--"; }
   };
   const timeString = `${safeFormat(startDate, timeFmt)} – ${safeFormat(endTime, timeFmt)}`;
-  const ariaLabel = `${event.title || t("events.no_title")}, ${timeString}${calendarName ? `, ${calendarName}` : ""}`;
+  // iTIP CANCEL marks the attendee's copy with status "cancelled" instead of
+  // deleting it (#572) - render it struck through and dimmed.
+  const isCancelled = event.status === "cancelled";
+  const ariaLabel = `${event.title || t("events.no_title")}, ${timeString}${calendarName ? `, ${calendarName}` : ""}${isCancelled ? `, ${t("detail.cancelled")}` : ""}`;
 
   const handleDragStart = useCallback((e: DragEvent) => {
     e.stopPropagation();
@@ -136,6 +139,7 @@ export function EventCard({ event, calendar, variant, onClick, onMouseEnter, onM
           "hover:opacity-80 transition-opacity",
           isSelected && "ring-2 ring-primary",
           isBeingDragged && "opacity-50",
+          isCancelled && !isBeingDragged && "opacity-60",
           className
         )}
         style={{ backgroundColor: `${color}20`, color, ...style }}
@@ -144,7 +148,7 @@ export function EventCard({ event, calendar, variant, onClick, onMouseEnter, onM
           className="w-1.5 h-1.5 rounded-full flex-shrink-0"
           style={{ backgroundColor: color }}
         />
-        <span className="truncate">{event.title || t("events.no_title")}</span>
+        <span className={cn("truncate", isCancelled && "line-through")}>{event.title || t("events.no_title")}</span>
       </button>
     );
   }
@@ -165,6 +169,7 @@ export function EventCard({ event, calendar, variant, onClick, onMouseEnter, onM
           continuesAfter && "pr-2",
           isSelected && "ring-2 ring-primary",
           isBeingDragged && "opacity-50",
+          isCancelled && !isBeingDragged && "opacity-60",
           className
         )}
         style={{ backgroundColor: `${color}24`, borderLeft: `3px solid ${color}`, color, ...style }}
@@ -173,7 +178,7 @@ export function EventCard({ event, calendar, variant, onClick, onMouseEnter, onM
           {showTimeInMonthView && !event.showWithoutTime && (
             <span className="flex-shrink-0 opacity-80">{format(startDate, timeFmt)}</span>
           )}
-          <span className="truncate font-medium">{event.title || t("events.no_title")}</span>
+          <span className={cn("truncate font-medium", isCancelled && "line-through")}>{event.title || t("events.no_title")}</span>
         </div>
       </button>
     );
@@ -193,11 +198,12 @@ export function EventCard({ event, calendar, variant, onClick, onMouseEnter, onM
         "hover:opacity-90 transition-opacity cursor-pointer",
         isSelected && "ring-2 ring-primary",
         isBeingDragged && "opacity-50",
+        isCancelled && !isBeingDragged && "opacity-60",
         className
       )}
       style={{ backgroundColor: `${color}30`, borderLeft: `3px solid ${color}`, color, ...style }}
     >
-      <div className="font-medium truncate">{event.title || t("events.no_title")}</div>
+      <div className={cn("font-medium truncate", isCancelled && "line-through")}>{event.title || t("events.no_title")}</div>
       {!event.showWithoutTime && (
         <div className="opacity-80 text-[10px]">
           {timeString}
diff --git a/components/calendar/event-detail-popover.tsx b/components/calendar/event-detail-popover.tsx
index 79af4181..750f284e 100644
--- a/components/calendar/event-detail-popover.tsx
+++ b/components/calendar/event-detail-popover.tsx
@@ -290,7 +290,10 @@ export function EventDetailPopover({
               className="w-2.5 h-2.5 rounded-full flex-shrink-0"
               style={{ backgroundColor: color }}
             />
-            <h3 className="text-base font-semibold truncate text-foreground">
+            <h3 className={cn(
+              "text-base font-semibold truncate text-foreground",
+              event.status === "cancelled" && "line-through text-muted-foreground"
+            )}>
               {event.title || t("events.no_title")}
             </h3>
           </div>
@@ -303,7 +306,7 @@ export function EventDetailPopover({
                 </span>
               )}
               {event.status === "cancelled" && (
-                <span className="ml-2 inline-flex items-center px-1.5 py-0.5 rounded text-[10px] font-medium bg-red-100 text-red-800 dark:bg-red-900/30 dark:text-red-400 line-through">
+                <span className="ml-2 inline-flex items-center px-1.5 py-0.5 rounded text-[10px] font-medium bg-red-100 text-red-800 dark:bg-red-900/30 dark:text-red-400">
                   {t("detail.cancelled")}
                 </span>
               )}
diff --git a/lib/__tests__/calendar-alerts.test.ts b/lib/__tests__/calendar-alerts.test.ts
index 5a791262..c57cd2ba 100644
--- a/lib/__tests__/calendar-alerts.test.ts
+++ b/lib/__tests__/calendar-alerts.test.ts
@@ -302,6 +302,19 @@ describe('getPendingAlerts', () => {
     expect(result).toHaveLength(0);
   });
 
+  it('skips alerts for cancelled events', () => {
+    // iTIP CANCEL marks the attendee's copy with status "cancelled" instead
+    // of deleting it (#572) - its reminders must not fire.
+    const event = makeEvent({
+      status: 'cancelled',
+      alerts: { 'a1': makeAlert() },
+    });
+    const calendars = [makeCalendar()];
+    const now = fiveMinBefore + 1000;
+    const result = getPendingAlerts([event], calendars, new Set(), now);
+    expect(result).toHaveLength(0);
+  });
+
   it('skips email action alerts', () => {
     const event = makeEvent({
       alerts: { 'a1': makeAlert({ action: 'email' }) },
diff --git a/lib/calendar-alerts.ts b/lib/calendar-alerts.ts
index 69de556f..f7b4f4c9 100644
--- a/lib/calendar-alerts.ts
+++ b/lib/calendar-alerts.ts
@@ -103,6 +103,8 @@ export function getPendingAlerts(
   const pending: PendingAlert[] = [];
 
   for (const event of events) {
+    if (event.status === 'cancelled') continue;
+
     const alerts = getEffectiveAlerts(event, calendars);
     if (!alerts) continue;