diff --git a/schema.graphqls b/schema.graphqls
index 6296660..c5a6726 100644
--- a/schema.graphqls
+++ b/schema.graphqls
@@ -63,6 +63,8 @@ type Shuttle {
 type Query {
   systems: [System!]!
   system(id: ID): System
+
+  isNotificationScheduled(input: NotificationInput!): Boolean
 }
 
 # Mutations
diff --git a/src/resolvers/QueryResolvers.ts b/src/resolvers/QueryResolvers.ts
index 8bb439d..98c8965 100644
--- a/src/resolvers/QueryResolvers.ts
+++ b/src/resolvers/QueryResolvers.ts
@@ -15,6 +15,10 @@ export const QueryResolvers: Resolvers<ServerContext> = {
         name: system.name,
         id: system.id,
       };
+    },
+    isNotificationScheduled: async (_parent, args, contextValue, _info) => {
+      const notificationData = args.input;
+      return contextValue.notificationService.isNotificationScheduled(notificationData);
     }
   },
-}
\ No newline at end of file
+}
diff --git a/src/services/NotificationService.ts b/src/services/NotificationService.ts
index c562986..573e2fb 100644
--- a/src/services/NotificationService.ts
+++ b/src/services/NotificationService.ts
@@ -250,4 +250,28 @@ export class NotificationService {
     }
     return this.deviceIdsToDeliverTo[tuple.toString()].has(deviceId);
   }
+
+  /**
+   * Return all scheduled notification for the given device ID.
+   * @param deviceId
+   */
+  public async getAllScheduledNotificationsForDevice(deviceId: string): Promise<ScheduledNotificationData[]> {
+    const scheduledNotifications: ScheduledNotificationData[] = [];
+
+    for (const key of Object.keys(this.deviceIdsToDeliverTo)) {
+      if (this.deviceIdsToDeliverTo[key].has(deviceId)) {
+        const tupleKey = TupleKey.fromExistingStringKey(key);
+        const shuttleId = tupleKey.tuple[0]
+        const stopId = tupleKey.tuple[1];
+
+        scheduledNotifications.push({
+          shuttleId,
+          stopId,
+          deviceId,
+        });
+      }
+    }
+
+    return scheduledNotifications;
+  }
 }
diff --git a/src/types/TupleKey.ts b/src/types/TupleKey.ts
index 08dcfb4..f95f4f0 100644
--- a/src/types/TupleKey.ts
+++ b/src/types/TupleKey.ts
@@ -16,4 +16,9 @@ export class TupleKey<T extends any[]> {
   valueOf(): string {
     return this.strKey;
   }
+
+  static fromExistingStringKey(strKey: string) {
+    const tuple = strKey.split(separator);
+    return new TupleKey(...tuple);
+  }
 }
diff --git a/test/resolvers/QueryResolverTests.test.ts b/test/resolvers/QueryResolverTests.test.ts
index af73aca..bb53d5b 100644
--- a/test/resolvers/QueryResolverTests.test.ts
+++ b/test/resolvers/QueryResolverTests.test.ts
@@ -2,6 +2,8 @@ import { describe, expect, it } from "@jest/globals";
 import { generateMockSystems } from "../testHelpers/mockDataGenerators";
 import { setupTestServerContext, setupTestServerHolder } from "../testHelpers/apolloTestServerHelpers";
 import assert = require("node:assert");
+import { ScheduledNotificationData } from "../../src/services/NotificationService";
+import { addMockShuttleToRepository, addMockStopToRepository } from "../testHelpers/repositorySetupHelpers";
 
 // See Apollo documentation for integration test guide
 // https://www.apollographql.com/docs/apollo-server/testing/testing
@@ -93,4 +95,63 @@ describe("QueryResolvers", () => {
       expect(response.body.singleResult.data?.system).toBeNull();
     });
   });
+
+  describe("isNotificationScheduled", () => {
+    const query = `
+    query IsNotificationScheduled($input: NotificationInput!) {
+      isNotificationScheduled(input: $input)
+    }
+    `
+
+    it("returns true if the notification is scheduled", async () => {
+      // Arrange
+      const shuttle = await addMockShuttleToRepository(context.repository, "1");
+      const stop = await addMockStopToRepository(context.repository, "1")
+
+      const notification: ScheduledNotificationData = {
+        shuttleId: shuttle.id,
+        stopId: stop.id,
+        deviceId: "1",
+      };
+      await context.notificationService.scheduleNotification(notification);
+
+      // Act
+      const response = await holder.testServer.executeOperation({
+        query,
+        variables: {
+          input: {
+            ...notification,
+          },
+        }
+      }, {
+        contextValue: context,
+      });
+
+      // Assert
+      assert(response.body.kind === "single");
+      expect(response.body.singleResult.errors).toBeUndefined();
+      expect(response.body.singleResult.data?.isNotificationScheduled).toBe(true);
+    });
+
+    it("returns false if the notification isn't scheduled", async () => {
+      // Act
+      const response = await holder.testServer.executeOperation({
+        query,
+        variables: {
+          input: {
+            shuttleId: "1",
+            stopId: "1",
+            deviceId: "1",
+          },
+        }
+      }, {
+        contextValue: context,
+      });
+
+      // Assert
+      assert(response.body.kind === "single");
+      expect(response.body.singleResult.errors).toBeUndefined();
+      expect(response.body.singleResult.data?.isNotificationScheduled).toBe(false);
+    });
+  });
 });
diff --git a/test/services/NotificationServiceTests.test.ts b/test/services/NotificationServiceTests.test.ts
index 7f3cfcf..8517727 100644
--- a/test/services/NotificationServiceTests.test.ts
+++ b/test/services/NotificationServiceTests.test.ts
@@ -230,4 +230,38 @@ describe("NotificationService", () => {
       expect(http2.connect as jest.Mock).toHaveBeenCalledTimes(0);
     });
   });
+
+  describe("getAllScheduledNotificationsForDevice", () => {
+    it("returns scheduled notifications for the device ID", async () => {
+      // Arrange
+      const shuttle1 = await addMockShuttleToRepository(repository, "1");
+      const stop = await addMockStopToRepository(repository, "1");
+      const { eta, notificationData1 } = generateNotificationDataAndEta(shuttle1, stop);
+      await notificationService.scheduleNotification(notificationData1);
+
+      const shuttle2 = {
+        ...shuttle1,
+        id: "2",
+      }
+      await repository.addOrUpdateShuttle(shuttle2);
+
+      const notificationData2 = {
+        ...notificationData1,
+        shuttleId: shuttle2.id,
+      }
+      await notificationService.scheduleNotification(notificationData2);
+
+      // Act
+      const notifications = await notificationService.getAllScheduledNotificationsForDevice(notificationData1.deviceId);
+
+      // Assert
+      expect(notifications.length).toBe(2);
+    });
+
+    it("returns an empty array if there are no notifications", async () => {
+      // Act
+      const notifications = await notificationService.getAllScheduledNotificationsForDevice("1");
+      expect(notifications.length).toBe(0);
+    });
+  });
 });
diff --git a/test/types/TupleKeyTests.test.ts b/test/types/TupleKeyTests.test.ts
index ac260dd..b04c3ec 100644
--- a/test/types/TupleKeyTests.test.ts
+++ b/test/types/TupleKeyTests.test.ts
@@ -28,4 +28,18 @@ describe("TupleKey", () => {
     expect(sampleObject[tupleKey1.toString()]).toEqual("value1");
     expect(sampleObject[(new TupleKey("1", "2")).toString()]).toEqual("value1");
   });
-});
\ No newline at end of file
+
+  describe("fromExistingStringKey", () => {
+    it("creates a new TupleKey from an existing string key", () => {
+      const strKey = "hello|there";
+      const tupleKey = TupleKey.fromExistingStringKey(strKey);
+      expect(tupleKey.toString()).toEqual(strKey);
+    });
+
+    it("creates an empty tuple if there is no string", () => {
+      const strKey = "";
+      const tupleKey = TupleKey.fromExistingStringKey(strKey);
+      expect(tupleKey.toString()).toEqual(strKey);
+    })
+  })
+});