diff --git a/application/src/main/java/org/thingsboard/server/service/entitiy/alarm/DefaultTbAlarmService.java b/application/src/main/java/org/thingsboard/server/service/entitiy/alarm/DefaultTbAlarmService.java
index caf65d39ec..141917f11f 100644
--- a/application/src/main/java/org/thingsboard/server/service/entitiy/alarm/DefaultTbAlarmService.java
+++ b/application/src/main/java/org/thingsboard/server/service/entitiy/alarm/DefaultTbAlarmService.java
@@ -29,6 +29,7 @@ import org.thingsboard.server.common.data.alarm.AlarmComment;
 import org.thingsboard.server.common.data.alarm.AlarmCommentType;
 import org.thingsboard.server.common.data.alarm.AlarmCreateOrUpdateActiveRequest;
 import org.thingsboard.server.common.data.alarm.AlarmInfo;
+import org.thingsboard.server.common.data.alarm.AlarmQueryV2;
 import org.thingsboard.server.common.data.alarm.AlarmUpdateRequest;
 import org.thingsboard.server.common.data.audit.ActionType;
 import org.thingsboard.server.common.data.exception.ThingsboardErrorCode;
@@ -36,9 +37,13 @@ import org.thingsboard.server.common.data.exception.ThingsboardException;
 import org.thingsboard.server.common.data.id.EdgeId;
 import org.thingsboard.server.common.data.id.TenantId;
 import org.thingsboard.server.common.data.id.UserId;
+import org.thingsboard.server.common.data.page.TimePageLink;
 import org.thingsboard.server.service.entitiy.AbstractTbEntityService;
 
 import java.util.List;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 
 @Service
 @AllArgsConstructor
@@ -210,6 +215,44 @@ public class DefaultTbAlarmService extends AbstractTbEntityService implements Tb
         return alarmInfo;
     }
 
+    @Override
+    public void unassignUserAlarms(TenantId tenantId, User user, long unassignTs) throws ThingsboardException {
+        AlarmQueryV2 alarmQuery = AlarmQueryV2.builder().assigneeId(user.getId()).pageLink(new TimePageLink(Integer.MAX_VALUE)).build();
+        try {
+            List<AlarmInfo> alarms = alarmService.findAlarmsV2(tenantId, alarmQuery).get(30, TimeUnit.SECONDS).getData();
+            if (alarms.isEmpty()) {
+                throw new ThingsboardException(ThingsboardErrorCode.ITEM_NOT_FOUND);
+            }
+            for (AlarmInfo alarm : alarms) {
+                AlarmApiCallResult result = alarmSubscriptionService.unassignAlarm(tenantId, alarm.getId(), getOrDefault(unassignTs));
+                if (!result.isSuccessful()) {
+                    continue;
+                }
+                if (result.isModified()) {
+                    AlarmComment alarmComment = AlarmComment.builder()
+                            .alarmId(alarm.getId())
+                            .type(AlarmCommentType.SYSTEM)
+                            .comment(JacksonUtil.newObjectNode().put("text", String.format("Alarm was unassigned because user %s - was deleted",
+                                            (user.getFirstName() == null || user.getLastName() == null) ? user.getName() : user.getFirstName() + " " + user.getLastName()))
+                                    .put("userId", user.getId().toString())
+                                    .put("subtype", "ASSIGN"))
+                            .build();
+                    try {
+                        alarmCommentService.saveAlarmComment(alarm, alarmComment, user);
+                    } catch (ThingsboardException e) {
+                        log.error("Failed to save alarm comment", e);
+                    }
+                    notificationEntityService.notifyCreateOrUpdateAlarm(result.getAlarm(), ActionType.ALARM_UNASSIGNED, user);
+                } else {
+                    throw new ThingsboardException("Alarm was already unassigned!", ThingsboardErrorCode.BAD_REQUEST_PARAMS);
+                }
+            }
+
+        } catch (InterruptedException | ExecutionException | TimeoutException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     @Override
     public Boolean delete(Alarm alarm, User user) {
         TenantId tenantId = alarm.getTenantId();
diff --git a/application/src/main/java/org/thingsboard/server/service/entitiy/alarm/TbAlarmService.java b/application/src/main/java/org/thingsboard/server/service/entitiy/alarm/TbAlarmService.java
index a2ae9c8cc7..ed4af5d1bd 100644
--- a/application/src/main/java/org/thingsboard/server/service/entitiy/alarm/TbAlarmService.java
+++ b/application/src/main/java/org/thingsboard/server/service/entitiy/alarm/TbAlarmService.java
@@ -19,6 +19,7 @@ import org.thingsboard.server.common.data.User;
 import org.thingsboard.server.common.data.alarm.Alarm;
 import org.thingsboard.server.common.data.alarm.AlarmInfo;
 import org.thingsboard.server.common.data.exception.ThingsboardException;
+import org.thingsboard.server.common.data.id.TenantId;
 import org.thingsboard.server.common.data.id.UserId;
 
 public interface TbAlarmService {
@@ -37,5 +38,7 @@ public interface TbAlarmService {
 
     AlarmInfo unassign(Alarm alarm, long unassignTs, User user) throws ThingsboardException;
 
+    void unassignUserAlarms(TenantId tenantId, User user, long unassignTs) throws ThingsboardException;
+
     Boolean delete(Alarm alarm, User user);
 }
diff --git a/application/src/main/java/org/thingsboard/server/service/entitiy/user/DefaultUserService.java b/application/src/main/java/org/thingsboard/server/service/entitiy/user/DefaultUserService.java
index c83c48cc8a..0c04e46ff5 100644
--- a/application/src/main/java/org/thingsboard/server/service/entitiy/user/DefaultUserService.java
+++ b/application/src/main/java/org/thingsboard/server/service/entitiy/user/DefaultUserService.java
@@ -30,6 +30,7 @@ import org.thingsboard.server.common.data.security.UserCredentials;
 import org.thingsboard.server.dao.user.UserService;
 import org.thingsboard.server.queue.util.TbCoreComponent;
 import org.thingsboard.server.service.entitiy.AbstractTbEntityService;
+import org.thingsboard.server.service.entitiy.alarm.TbAlarmService;
 import org.thingsboard.server.service.security.system.SystemSecurityService;
 
 import javax.servlet.http.HttpServletRequest;
@@ -43,6 +44,7 @@ import static org.thingsboard.server.controller.UserController.ACTIVATE_URL_PATT
 public class DefaultUserService extends AbstractTbEntityService implements TbUserService {
 
     private final UserService userService;
+    private final TbAlarmService tbAlarmService;
     private final MailService mailService;
     private final SystemSecurityService systemSecurityService;
 
@@ -80,6 +82,7 @@ public class DefaultUserService extends AbstractTbEntityService implements TbUse
         UserId userId = tbUser.getId();
 
         try {
+            tbAlarmService.unassignUserAlarms(tenantId, tbUser, System.currentTimeMillis());
             userService.deleteUser(tenantId, userId);
             notificationEntityService.notifyCreateOrUpdateOrDelete(tenantId, customerId, userId, tbUser,
                     user, ActionType.DELETED, true, null, customerId.toString());