diff --git a/prisma/migrations/20260304233528_add_tickets/migration.sql b/prisma/migrations/20260304233528_add_tickets/migration.sql
new file mode 100644
index 0000000..a758db2
--- /dev/null
+++ b/prisma/migrations/20260304233528_add_tickets/migration.sql
@@ -0,0 +1,73 @@
+-- CreateEnum
+CREATE TYPE "TicketStatus" AS ENUM ('OPEN', 'ASSIGNED', 'RESOLVED', 'CLOSED');
+
+-- CreateEnum
+CREATE TYPE "TicketPriority" AS ENUM ('LOW', 'MEDIUM', 'HIGH', 'URGENT');
+
+-- CreateEnum
+CREATE TYPE "TicketSource" AS ENUM ('STAFF', 'SUBSCRIBER');
+
+-- CreateTable
+CREATE TABLE "TicketCategory" (
+    "id" TEXT NOT NULL,
+    "tenantId" TEXT NOT NULL,
+    "name" TEXT NOT NULL,
+    "description" TEXT,
+    "isActive" BOOLEAN NOT NULL DEFAULT true,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+
+    CONSTRAINT "TicketCategory_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateTable
+CREATE TABLE "Ticket" (
+    "id" TEXT NOT NULL,
+    "tenantId" TEXT NOT NULL,
+    "ticketNumber" TEXT NOT NULL,
+    "subject" TEXT NOT NULL,
+    "description" TEXT NOT NULL,
+    "categoryId" TEXT NOT NULL,
+    "priority" "TicketPriority" NOT NULL DEFAULT 'MEDIUM',
+    "status" "TicketStatus" NOT NULL DEFAULT 'OPEN',
+    "source" "TicketSource" NOT NULL DEFAULT 'STAFF',
+    "subscriberId" TEXT,
+    "createdById" TEXT NOT NULL,
+    "resolvedAt" TIMESTAMP(3),
+    "closedAt" TIMESTAMP(3),
+    "notes" TEXT,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+
+    CONSTRAINT "Ticket_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE INDEX "TicketCategory_tenantId_idx" ON "TicketCategory"("tenantId");
+
+-- CreateIndex
+CREATE UNIQUE INDEX "TicketCategory_tenantId_name_key" ON "TicketCategory"("tenantId", "name");
+
+-- CreateIndex
+CREATE INDEX "Ticket_tenantId_idx" ON "Ticket"("tenantId");
+
+-- CreateIndex
+CREATE INDEX "Ticket_tenantId_status_idx" ON "Ticket"("tenantId", "status");
+
+-- CreateIndex
+CREATE INDEX "Ticket_tenantId_categoryId_idx" ON "Ticket"("tenantId", "categoryId");
+
+-- CreateIndex
+CREATE INDEX "Ticket_subscriberId_idx" ON "Ticket"("subscriberId");
+
+-- CreateIndex
+CREATE UNIQUE INDEX "Ticket_tenantId_ticketNumber_key" ON "Ticket"("tenantId", "ticketNumber");
+
+-- AddForeignKey
+ALTER TABLE "Ticket" ADD CONSTRAINT "Ticket_categoryId_fkey" FOREIGN KEY ("categoryId") REFERENCES "TicketCategory"("id") ON DELETE RESTRICT ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "Ticket" ADD CONSTRAINT "Ticket_subscriberId_fkey" FOREIGN KEY ("subscriberId") REFERENCES "Subscriber"("id") ON DELETE SET NULL ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "Ticket" ADD CONSTRAINT "Ticket_createdById_fkey" FOREIGN KEY ("createdById") REFERENCES "User"("id") ON DELETE RESTRICT ON UPDATE CASCADE;
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 016e60c..b0c5237 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -100,6 +100,25 @@ enum PaymentStatus {
   VOIDED
 }
 
+enum TicketStatus {
+  OPEN
+  ASSIGNED
+  RESOLVED
+  CLOSED
+}
+
+enum TicketPriority {
+  LOW
+  MEDIUM
+  HIGH
+  URGENT
+}
+
+enum TicketSource {
+  STAFF
+  SUBSCRIBER
+}
+
 // =============================================================================
 // MODELS
 // =============================================================================
@@ -258,6 +277,7 @@ model Subscriber {
 
   invoices      Invoice[]
   payments      Payment[]
+  tickets       Ticket[]
 
   /// Account numbers must be unique within a tenant
   @@unique([tenantId, accountNumber])
@@ -340,6 +360,8 @@ model User {
   recordedPayments Payment[] @relation("PaymentRecordedBy")
   /// Zone assignments for collector role (which zones this user can collect from)
   zoneAssignments ZoneAssignment[]
+  /// Tickets this user created (staff or subscriber portal)
+  createdTickets  Ticket[]         @relation("TicketCreatedBy")
 
   createdAt DateTime @default(now())
   updatedAt DateTime @updatedAt
@@ -529,6 +551,63 @@ model PaymentAllocation {
   @@index([tenantId])
 }
 
+/// A TicketCategory is an admin-configurable label for classifying support tickets.
+/// Default ISP categories are seeded at tenant creation.
+/// Deactivated categories (isActive=false) cannot be used for new tickets.
+model TicketCategory {
+  id          String   @id @default(uuid())
+  tenantId    String
+  name        String
+  description String?
+  isActive    Boolean  @default(true)
+  createdAt   DateTime @default(now())
+  updatedAt   DateTime @updatedAt
+
+  tickets     Ticket[]
+
+  /// Category names must be unique within a tenant
+  @@unique([tenantId, name])
+  /// RLS-ready index — always present on tenant-scoped models
+  @@index([tenantId])
+}
+
+/// A Ticket records a support request from a subscriber or staff member.
+/// Tickets follow the lifecycle: OPEN -> ASSIGNED -> RESOLVED -> CLOSED.
+/// Status transitions are validated by the ticket service guard map.
+model Ticket {
+  id           String         @id @default(uuid())
+  tenantId     String
+  /// Auto-generated sequential identifier per tenant (e.g., "TKT-0001")
+  ticketNumber String
+  subject      String
+  description  String
+  categoryId   String
+  category     TicketCategory @relation(fields: [categoryId], references: [id])
+  priority     TicketPriority @default(MEDIUM)
+  status       TicketStatus   @default(OPEN)
+  source       TicketSource   @default(STAFF)
+  /// The subscriber this ticket is about (optional — not all tickets are subscriber-specific)
+  subscriberId String?
+  subscriber   Subscriber?    @relation(fields: [subscriberId], references: [id])
+  /// The staff member or subscriber who created this ticket
+  createdById  String
+  createdBy    User           @relation("TicketCreatedBy", fields: [createdById], references: [id])
+  resolvedAt   DateTime?
+  closedAt     DateTime?
+  /// Internal staff notes
+  notes        String?
+  createdAt    DateTime       @default(now())
+  updatedAt    DateTime       @updatedAt
+
+  /// Ticket numbers must be unique within a tenant
+  @@unique([tenantId, ticketNumber])
+  /// RLS-ready index — always present on tenant-scoped models
+  @@index([tenantId])
+  @@index([tenantId, status])
+  @@index([tenantId, categoryId])
+  @@index([subscriberId])
+}
+
 /// A single line item on an Invoice (e.g., "50 Mbps Monthly Service — $49.99").
 model InvoiceLine {
   id          String   @id @default(uuid())
diff --git a/src/lib/prisma-tenant.ts b/src/lib/prisma-tenant.ts
index b241944..376425f 100644
--- a/src/lib/prisma-tenant.ts
+++ b/src/lib/prisma-tenant.ts
@@ -30,7 +30,7 @@ import { prisma } from "@/lib/prisma";
  * Extend this list as new models are added in later phases:
  * e.g., "subscriber", "invoice", "servicePlan", "payment"
  */
-export const TENANT_SCOPED_MODELS = ["user", "account", "accountingPeriod", "subscriber", "servicePlan", "tenantSettings", "journalEntry", "journalEntryLine", "invoice", "invoiceLine", "payment", "paymentAllocation", "zone", "zoneAssignment"] as const;
+export const TENANT_SCOPED_MODELS = ["user", "account", "accountingPeriod", "subscriber", "servicePlan", "tenantSettings", "journalEntry", "journalEntryLine", "invoice", "invoiceLine", "payment", "paymentAllocation", "zone", "zoneAssignment", "ticket", "ticketCategory"] as const;
 
 export type TenantScopedModel = (typeof TENANT_SCOPED_MODELS)[number];
 
@@ -1128,6 +1128,198 @@ export function withTenantContext(tenantId: string) {
           return query(args);
         },
       },
+
+      ticketCategory: {
+        async findMany({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async findFirst({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async findFirstOrThrow({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async findUnique({ args, query }) {
+          if (args.where && "id" in args.where && !("tenantId" in (args.where as object))) {
+            return prisma.ticketCategory.findFirst({
+              ...args,
+              where: { ...args.where, tenantId },
+            });
+          }
+          return query(args);
+        },
+
+        async findUniqueOrThrow({ args, query }) {
+          if (args.where && "id" in args.where && !("tenantId" in (args.where as object))) {
+            const result = await prisma.ticketCategory.findFirst({
+              ...args,
+              where: { ...args.where, tenantId },
+            });
+            if (!result) {
+              throw new Error("Record not found");
+            }
+            return result;
+          }
+          return query(args);
+        },
+
+        async create({ args, query }) {
+          args.data = { ...args.data, tenantId } as typeof args.data;
+          return query(args);
+        },
+
+        async createMany({ args, query }) {
+          if (Array.isArray(args.data)) {
+            args.data = args.data.map((item) => ({ ...item, tenantId })) as typeof args.data;
+          } else {
+            args.data = { ...args.data, tenantId } as typeof args.data;
+          }
+          return query(args);
+        },
+
+        async update({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async updateMany({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async delete({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async deleteMany({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async upsert({ args, query }) {
+          args.where = { ...args.where, tenantId } as typeof args.where;
+          args.create = { ...args.create, tenantId } as typeof args.create;
+          return query(args);
+        },
+
+        async count({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async aggregate({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async groupBy({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+      },
+
+      ticket: {
+        async findMany({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async findFirst({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async findFirstOrThrow({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async findUnique({ args, query }) {
+          if (args.where && "id" in args.where && !("tenantId" in (args.where as object))) {
+            return prisma.ticket.findFirst({
+              ...args,
+              where: { ...args.where, tenantId },
+            });
+          }
+          return query(args);
+        },
+
+        async findUniqueOrThrow({ args, query }) {
+          if (args.where && "id" in args.where && !("tenantId" in (args.where as object))) {
+            const result = await prisma.ticket.findFirst({
+              ...args,
+              where: { ...args.where, tenantId },
+            });
+            if (!result) {
+              throw new Error("Record not found");
+            }
+            return result;
+          }
+          return query(args);
+        },
+
+        async create({ args, query }) {
+          args.data = { ...args.data, tenantId } as typeof args.data;
+          return query(args);
+        },
+
+        async createMany({ args, query }) {
+          if (Array.isArray(args.data)) {
+            args.data = args.data.map((item) => ({ ...item, tenantId })) as typeof args.data;
+          } else {
+            args.data = { ...args.data, tenantId } as typeof args.data;
+          }
+          return query(args);
+        },
+
+        async update({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async updateMany({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async delete({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async deleteMany({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async upsert({ args, query }) {
+          args.where = { ...args.where, tenantId } as typeof args.where;
+          args.create = { ...args.create, tenantId } as typeof args.create;
+          return query(args);
+        },
+
+        async count({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async aggregate({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+
+        async groupBy({ args, query }) {
+          args.where = { ...args.where, tenantId };
+          return query(args);
+        },
+      },
     },
   });
 }
diff --git a/src/lib/tenant.ts b/src/lib/tenant.ts
index d75d00d..45d3da7 100644
--- a/src/lib/tenant.ts
+++ b/src/lib/tenant.ts
@@ -198,6 +198,18 @@ export async function createTenant(input: CreateTenantInput): Promise<CreateTena
     // if anything fails, neither the tenant, user, nor COA are persisted.
     await seedChartOfAccounts(tx, tenant.id);
 
+    // Seed default ISP ticket categories for this tenant.
+    // These provide a sensible starting set — admins can add/deactivate later.
+    const defaultCategories = [
+      { name: "No Connection", description: "Subscriber has no internet connection", tenantId: tenant.id },
+      { name: "Slow Speed", description: "Connection speed below expected plan speed", tenantId: tenant.id },
+      { name: "Billing Inquiry", description: "Questions about bills or payments", tenantId: tenant.id },
+      { name: "New Installation", description: "Request for new service installation", tenantId: tenant.id },
+      { name: "Equipment Issue", description: "Router, ONU, or cable problems", tenantId: tenant.id },
+      { name: "Other", description: "Other issues not covered by categories above", tenantId: tenant.id },
+    ];
+    await tx.ticketCategory.createMany({ data: defaultCategories });
+
     return { tenant, user };
   });