diff --git a/apps/api/src/api/v1/sentry_webhook.py b/apps/api/src/api/v1/sentry_webhook.py
index e189c17d..cc1bfac4 100644
--- a/apps/api/src/api/v1/sentry_webhook.py
+++ b/apps/api/src/api/v1/sentry_webhook.py
@@ -29,6 +29,7 @@ from src.models.approval import (
     RiskLevel,
 )
 from src.services.approval_db import get_approval_service
+from src.services.sentry_service import get_sentry_service
 from src.services.telegram_gateway import get_telegram_gateway
 from src.utils.timezone import now_taipei_iso
 
@@ -48,6 +49,9 @@ SENTRY_LEVEL_TO_RISK = {
     "info": RiskLevel.LOW,
 }
 
+# 去重配置 (Phase 10.2.1 - 2026-03-27)
+SENTRY_DEDUP_TTL = 600  # 10 分鐘內不重複發送同一 issue
+
 
 class SentryIssuePayload(BaseModel):
     """Sentry Issue Alert Payload (簡化版)"""
@@ -94,6 +98,12 @@ async def handle_sentry_error(
 
         # 提取錯誤資訊
         issue_data = payload.get("data", {}).get("issue", {})
+
+        # Phase 10.2.1: 去重檢查 (10 分鐘內不重複發送)
+        issue_id = issue_data.get("id")
+        sentry_service = get_sentry_service()
+        if not await sentry_service.check_dedup(issue_id, ttl=SENTRY_DEDUP_TTL):
+            return {"status": "deduplicated", "issue_id": issue_id, "ttl": SENTRY_DEDUP_TTL}
         event_data = payload.get("data", {}).get("event", {})
 
         error_context = {
diff --git a/apps/api/src/services/sentry_service.py b/apps/api/src/services/sentry_service.py
index 93e993fd..209782de 100644
--- a/apps/api/src/services/sentry_service.py
+++ b/apps/api/src/services/sentry_service.py
@@ -196,6 +196,40 @@ class SentryService:
         """取得 Issue 在 Sentry UI 的連結"""
         return f"{self.base_url}/organizations/{self.org}/issues/{issue_id}/"
 
+    # =========================================================================
+    # Dedup (Phase 10.2.1 - 2026-03-27)
+    # =========================================================================
+
+    async def check_dedup(self, issue_id: str, ttl: int = 600) -> bool:
+        """
+        檢查 Sentry Issue 是否已在去重窗口內
+
+        Args:
+            issue_id: Sentry Issue ID
+            ttl: 去重窗口秒數 (預設 10 分鐘)
+
+        Returns:
+            bool: True = 應處理, False = 已去重跳過
+        """
+        from src.core.redis_client import get_redis_pool
+
+        if not issue_id:
+            return True
+
+        redis = await get_redis_pool()
+        key = f"sentry_dedup:{issue_id}"
+
+        # 檢查是否已存在
+        exists = await redis.exists(key)
+        if exists:
+            logger.info("sentry_dedup_hit", issue_id=issue_id)
+            return False
+
+        # 設置去重標記
+        await redis.setex(key, ttl, "1")
+        logger.debug("sentry_dedup_set", issue_id=issue_id, ttl=ttl)
+        return True
+
 
 # =============================================================================
 # Singleton