diff --git a/__tests__/alerts.ts b/__tests__/alerts.ts
index 27cc48aa3d..4f6870b613 100644
--- a/__tests__/alerts.ts
+++ b/__tests__/alerts.ts
@@ -429,3 +429,103 @@ describe('mutation clearOpportunityAlert', () => {
     expect(alerts.opportunityId).toBeNull();
   });
 });
+
+describe('mutation updateHasSeenOpportunity', () => {
+  const MUTATION = (hasSeenOpportunity?: boolean) => /* GraphQL */ `
+    mutation UpdateHasSeenOpportunity {
+      updateHasSeenOpportunity${hasSeenOpportunity !== undefined ? `(hasSeenOpportunity: ${hasSeenOpportunity})` : ''} {
+        _
+      }
+    }
+  `;
+
+  it('should not authorize when not logged in', () =>
+    testMutationErrorCode(client, { mutation: MUTATION() }, 'UNAUTHENTICATED'));
+
+  it('should set hasSeenOpportunity flag to true by default', async () => {
+    loggedUser = '1';
+
+    await con.getRepository(Alerts).save(
+      con.getRepository(Alerts).create({
+        userId: '1',
+        flags: { hasSeenOpportunity: false },
+      }),
+    );
+
+    const res = await client.mutate(MUTATION());
+    expect(res.errors).toBeFalsy();
+    const alerts = await con.getRepository(Alerts).findOneBy({ userId: '1' });
+    expect(alerts.flags.hasSeenOpportunity).toBe(true);
+  });
+
+  it('should set hasSeenOpportunity flag to true when explicitly passed', async () => {
+    loggedUser = '1';
+
+    await con.getRepository(Alerts).save(
+      con.getRepository(Alerts).create({
+        userId: '1',
+        flags: { hasSeenOpportunity: false },
+      }),
+    );
+
+    const res = await client.mutate(MUTATION(true));
+    expect(res.errors).toBeFalsy();
+    const alerts = await con.getRepository(Alerts).findOneBy({ userId: '1' });
+    expect(alerts.flags.hasSeenOpportunity).toBe(true);
+  });
+
+  it('should set hasSeenOpportunity flag to false when passed', async () => {
+    loggedUser = '1';
+
+    await con.getRepository(Alerts).save(
+      con.getRepository(Alerts).create({
+        userId: '1',
+        flags: { hasSeenOpportunity: true },
+      }),
+    );
+
+    const res = await client.mutate(MUTATION(false));
+    expect(res.errors).toBeFalsy();
+    const alerts = await con.getRepository(Alerts).findOneBy({ userId: '1' });
+    expect(alerts.flags.hasSeenOpportunity).toBe(false);
+  });
+
+  it('should preserve existing flags when updating hasSeenOpportunity', async () => {
+    loggedUser = '1';
+
+    const lastReferralDate = new Date('2023-02-05 12:00:00');
+    await con.getRepository(Alerts).save(
+      con.getRepository(Alerts).create({
+        userId: '1',
+        flags: {
+          hasSeenOpportunity: false,
+          lastReferralReminder: lastReferralDate,
+        },
+      }),
+    );
+
+    const res = await client.mutate(MUTATION(true));
+    expect(res.errors).toBeFalsy();
+    const alerts = await con.getRepository(Alerts).findOneBy({ userId: '1' });
+    expect(alerts.flags.hasSeenOpportunity).toBe(true);
+    // JSONB stores dates as ISO strings
+    expect(alerts.flags.lastReferralReminder).toEqual(
+      lastReferralDate.toISOString(),
+    );
+  });
+
+  it('should work when alerts record does not have flags set', async () => {
+    loggedUser = '1';
+
+    await con.getRepository(Alerts).save(
+      con.getRepository(Alerts).create({
+        userId: '1',
+      }),
+    );
+
+    const res = await client.mutate(MUTATION());
+    expect(res.errors).toBeFalsy();
+    const alerts = await con.getRepository(Alerts).findOneBy({ userId: '1' });
+    expect(alerts.flags.hasSeenOpportunity).toBe(true);
+  });
+});
diff --git a/src/schema/alerts.ts b/src/schema/alerts.ts
index cb2f53688c..429834fbe7 100644
--- a/src/schema/alerts.ts
+++ b/src/schema/alerts.ts
@@ -5,6 +5,7 @@ import { AuthContext, BaseContext, Context } from '../Context';
 import { DataSource, QueryRunner } from 'typeorm';
 import { insertOrIgnoreAction } from './actions';
 import { GQLEmptyResponse } from './common';
+import { updateFlagsStatement } from '../common';
 
 interface GQLAlerts {
   filter: boolean;
@@ -189,6 +190,13 @@ export const typeDefs = /* GraphQL */ `
     Reset opportunity alert
     """
     clearOpportunityAlert: EmptyResponse! @auth
+
+    """
+    Update the hasSeenOpportunity flag
+    """
+    updateHasSeenOpportunity(
+      hasSeenOpportunity: Boolean = true
+    ): EmptyResponse! @auth
   }
 
   extend type Query {
@@ -314,6 +322,19 @@ export const resolvers: IResolvers<unknown, BaseContext> = traceResolvers<
       await updateAlerts(ctx.con, ctx.userId, { opportunityId: null });
       return { _: true };
     },
+    updateHasSeenOpportunity: async (
+      _,
+      { hasSeenOpportunity = true }: { hasSeenOpportunity?: boolean },
+      ctx: AuthContext,
+    ): Promise<GQLEmptyResponse> => {
+      await ctx.con.getRepository(Alerts).update(
+        { userId: ctx.userId },
+        {
+          flags: updateFlagsStatement<Alerts>({ hasSeenOpportunity }),
+        },
+      );
+      return { _: true };
+    },
   },
   Query: {
     userAlerts: (_, __, ctx: Context): Promise<GQLAlerts> | GQLAlerts =>