diff --git a/src/lib/server/db/central-schema.ts b/src/lib/server/db/central-schema.ts
index c7cf930..6361698 100644
--- a/src/lib/server/db/central-schema.ts
+++ b/src/lib/server/db/central-schema.ts
@@ -242,6 +242,8 @@ export const userInvite = pgTable(
 export const challengeThrottle = pgTable("challenge_throttle", {
   /** Primary key - identifier (email hash for PIN challenges, email for passkey challenges) */
   id: text("id").primaryKey(),
+  /** Tenant ID for scoping throttles to single tenants to restrict global lock-out. Might be null for global throttles on administrative accounts */
+  tenantId: uuid("tenant_id").references(() => tenant.id, { onDelete: "cascade" }),
   /** Number of failed attempts */
   failedAttempts: integer("failed_attempts").default(0).notNull(),
   /** When the throttle was last updated */
diff --git a/src/lib/server/services/__tests__/appointment-service.test.ts b/src/lib/server/services/__tests__/appointment-service.test.ts
index afc1027..12c4fa5 100644
--- a/src/lib/server/services/__tests__/appointment-service.test.ts
+++ b/src/lib/server/services/__tests__/appointment-service.test.ts
@@ -853,7 +853,11 @@ describe("AppointmentService", () => {
       );
 
       expect(challengeStore.consume).toHaveBeenCalledWith("challenge-123", "tenant-123");
-      expect(challengeThrottleService.clearThrottle).toHaveBeenCalledWith("email-hash-123", "pin");
+      expect(challengeThrottleService.clearThrottle).toHaveBeenCalledWith(
+        "email-hash-123",
+        "pin",
+        "tenant-123",
+      );
     });
 
     it("should throw NotFoundError when challenge is not found", async () => {
@@ -922,6 +926,7 @@ describe("AppointmentService", () => {
       expect(challengeThrottleService.recordFailedAttempt).toHaveBeenCalledWith(
         "email-hash-123",
         "pin",
+        "tenant-123",
       );
     });
 
diff --git a/src/lib/server/services/appointment-service.ts b/src/lib/server/services/appointment-service.ts
index e0be8a6..a80ffd9 100644
--- a/src/lib/server/services/appointment-service.ts
+++ b/src/lib/server/services/appointment-service.ts
@@ -1001,13 +1001,13 @@ export class AppointmentService {
       });
 
       // Record failed attempt for throttling
-      await challengeThrottleService.recordFailedAttempt(emailHash, "pin");
+      await challengeThrottleService.recordFailedAttempt(emailHash, "pin", this.tenantId);
 
       throw new ValidationError("Invalid challenge response");
     }
 
     // Clear throttle on successful verification
-    await challengeThrottleService.clearThrottle(emailHash, "pin");
+    await challengeThrottleService.clearThrottle(emailHash, "pin", this.tenantId);
 
     const db = await this.getDb();
 
diff --git a/src/lib/server/services/challenge-throttle.ts b/src/lib/server/services/challenge-throttle.ts
index 5c36b69..130bd7f 100644
--- a/src/lib/server/services/challenge-throttle.ts
+++ b/src/lib/server/services/challenge-throttle.ts
@@ -9,7 +9,7 @@
 
 import { centralDb } from "$lib/server/db";
 import { challengeThrottle } from "$lib/server/db/central-schema";
-import { eq, lt, sql } from "drizzle-orm";
+import { eq, lt, sql, and } from "drizzle-orm";
 import { logger } from "$lib/logger";
 
 export type ThrottleType = "pin" | "passkey" | "passphrase";
@@ -51,15 +51,25 @@ class ChallengeThrottleService {
    * Check if a challenge request should be throttled
    * @param identifier - Email hash for PIN challenges, email for passkey challenges
    * @param type - Type of challenge (pin or passkey)
+   * @param tenantId - Tenant ID for scoping the throttle check
    */
-  async checkThrottle(identifier: string, type: ThrottleType): Promise<ThrottleResult> {
+  async checkThrottle(
+    identifier: string,
+    type: ThrottleType,
+    tenantId?: string,
+  ): Promise<ThrottleResult> {
     const now = new Date();
 
     // Get throttle record from central DB
     const records = await centralDb
       .select()
       .from(challengeThrottle)
-      .where(eq(challengeThrottle.id, identifier))
+      .where(
+        and(
+          eq(challengeThrottle.id, identifier),
+          tenantId ? eq(challengeThrottle.tenantId, tenantId) : undefined,
+        ),
+      )
       .limit(1);
 
     if (records.length === 0) {
@@ -72,7 +82,14 @@ class ChallengeThrottleService {
     // Check if throttle has expired
     if (now > record.resetAt) {
       // Throttle expired, clean up and allow
-      await centralDb.delete(challengeThrottle).where(eq(challengeThrottle.id, identifier));
+      await centralDb
+        .delete(challengeThrottle)
+        .where(
+          and(
+            eq(challengeThrottle.id, identifier),
+            tenantId ? eq(challengeThrottle.tenantId, tenantId) : undefined,
+          ),
+        );
       return { allowed: true, retryAfterMs: 0, failedAttempts: 0 };
     }
 
@@ -104,8 +121,13 @@ class ChallengeThrottleService {
    * Record a failed challenge attempt
    * @param identifier - Email hash for PIN challenges, email for passkey challenges
    * @param type - Type of challenge (pin or passkey)
+   * @param tenantId - Tenant ID for scoping the throttle record
    */
-  async recordFailedAttempt(identifier: string, type: ThrottleType): Promise<void> {
+  async recordFailedAttempt(
+    identifier: string,
+    type: ThrottleType,
+    tenantId?: string,
+  ): Promise<void> {
     const now = new Date();
 
     const resetAt = new Date(now.getTime() + THROTTLE_RESET_DURATION_MS);
@@ -116,6 +138,7 @@ class ChallengeThrottleService {
         failedAttempts: 1,
         lastAttemptAt: now,
         resetAt,
+        tenantId: tenantId,
       })
       .onConflictDoUpdate({
         target: challengeThrottle.id,
@@ -135,9 +158,17 @@ class ChallengeThrottleService {
    * Clear throttle for successful authentication
    * @param identifier - Email hash for PIN challenges, email for passkey challenges
    * @param type - Type of challenge (pin or passkey)
+   * @param tenantId - Tenant ID for scoping the throttle clearance
    */
-  async clearThrottle(identifier: string, type: ThrottleType): Promise<void> {
-    await centralDb.delete(challengeThrottle).where(eq(challengeThrottle.id, identifier));
+  async clearThrottle(identifier: string, type: ThrottleType, tenantId?: string): Promise<void> {
+    await centralDb
+      .delete(challengeThrottle)
+      .where(
+        and(
+          eq(challengeThrottle.id, identifier),
+          tenantId ? eq(challengeThrottle.tenantId, tenantId) : undefined,
+        ),
+      );
 
     logger.debug(`Cleared ${type} challenge throttle`, {
       identifier: identifier.slice(0, 8),
diff --git a/src/routes/api/tenants/[id]/appointments/bootstrap-challenge/+server.ts b/src/routes/api/tenants/[id]/appointments/bootstrap-challenge/+server.ts
index 898dc60..7891ce9 100644
--- a/src/routes/api/tenants/[id]/appointments/bootstrap-challenge/+server.ts
+++ b/src/routes/api/tenants/[id]/appointments/bootstrap-challenge/+server.ts
@@ -107,7 +107,11 @@ export const POST: RequestHandler = async ({ request, params }) => {
       emailHash: body.emailHash,
     });
 
-    const throttleResult = await challengeThrottleService.checkThrottle(binding, "passkey");
+    const throttleResult = await challengeThrottleService.checkThrottle(
+      binding,
+      "passkey",
+      tenantId,
+    );
     if (!throttleResult.allowed) {
       return json(
         {
diff --git a/src/routes/api/tenants/[id]/appointments/bootstrap-verify/+server.ts b/src/routes/api/tenants/[id]/appointments/bootstrap-verify/+server.ts
index 1c237f1..6e5285b 100644
--- a/src/routes/api/tenants/[id]/appointments/bootstrap-verify/+server.ts
+++ b/src/routes/api/tenants/[id]/appointments/bootstrap-verify/+server.ts
@@ -124,7 +124,7 @@ export const POST: RequestHandler = async ({ request, params }) => {
     }
 
     if (storedChallenge.emailHash !== binding) {
-      await challengeThrottleService.recordFailedAttempt(binding, "passkey");
+      await challengeThrottleService.recordFailedAttempt(binding, "passkey", tenantId);
       throw new ValidationError("Invalid bootstrap challenge binding");
     }
 
@@ -136,11 +136,11 @@ export const POST: RequestHandler = async ({ request, params }) => {
     });
 
     if (!matchesPowDifficulty(digest, NEW_CLIENT_BOOTSTRAP_DIFFICULTY)) {
-      await challengeThrottleService.recordFailedAttempt(binding, "passkey");
+      await challengeThrottleService.recordFailedAttempt(binding, "passkey", tenantId);
       throw new ValidationError("Invalid bootstrap proof of work");
     }
 
-    await challengeThrottleService.clearThrottle(binding, "passkey");
+    await challengeThrottleService.clearThrottle(binding, "passkey", tenantId);
 
     const bookingAccessToken = await generateNewClientBootstrapToken({
       tenantId,
diff --git a/src/routes/api/tenants/[id]/appointments/challenge/+server.ts b/src/routes/api/tenants/[id]/appointments/challenge/+server.ts
index 7ec1eab..134b196 100644
--- a/src/routes/api/tenants/[id]/appointments/challenge/+server.ts
+++ b/src/routes/api/tenants/[id]/appointments/challenge/+server.ts
@@ -139,7 +139,7 @@ export const POST: RequestHandler = async ({ request, params }) => {
     const { emailHash } = requestSchema.parse(body);
 
     // Check throttling
-    const throttleResult = await challengeThrottleService.checkThrottle(emailHash, "pin");
+    const throttleResult = await challengeThrottleService.checkThrottle(emailHash, "pin", tenantId);
 
     if (!throttleResult.allowed) {
       logger.warn("PIN challenge throttled", {
diff --git a/src/routes/api/tenants/[id]/appointments/verify-challenge/+server.ts b/src/routes/api/tenants/[id]/appointments/verify-challenge/+server.ts
index 9e42657..e141130 100644
--- a/src/routes/api/tenants/[id]/appointments/verify-challenge/+server.ts
+++ b/src/routes/api/tenants/[id]/appointments/verify-challenge/+server.ts
@@ -169,7 +169,11 @@ export const POST: RequestHandler = async ({ request, params }) => {
       });
 
       // Record failed attempt for throttling
-      await challengeThrottleService.recordFailedAttempt(storedChallenge.emailHash, "pin");
+      await challengeThrottleService.recordFailedAttempt(
+        storedChallenge.emailHash,
+        "pin",
+        tenantId,
+      );
 
       throw new ValidationError("Invalid challenge response");
     }
@@ -209,7 +213,7 @@ export const POST: RequestHandler = async ({ request, params }) => {
     });
 
     // Clear throttle on successful verification
-    await challengeThrottleService.clearThrottle(storedChallenge.emailHash, "pin");
+    await challengeThrottleService.clearThrottle(storedChallenge.emailHash, "pin", tenantId);
 
     const response: ChallengeVerificationResponse = {
       valid: true,