diff --git a/src/stores/invoices.ts b/src/stores/invoices.ts
new file mode 100644
index 0000000..a9760c4
--- /dev/null
+++ b/src/stores/invoices.ts
@@ -0,0 +1,138 @@
+import { defineStore } from 'pinia'
+import { ref } from 'vue'
+import { invoke } from '@tauri-apps/api/core'
+
+export interface Invoice {
+  id?: number
+  client_id: number
+  invoice_number: string
+  date: string
+  due_date?: string
+  subtotal: number
+  tax_rate: number
+  tax_amount: number
+  discount: number
+  total: number
+  notes?: string
+  status: string
+  template_id?: string
+}
+
+export interface InvoiceItem {
+  id?: number
+  invoice_id: number
+  description: string
+  quantity: number
+  rate: number
+  amount: number
+  time_entry_id?: number
+}
+
+export const useInvoicesStore = defineStore('invoices', () => {
+  const invoices = ref<Invoice[]>([])
+  const loading = ref(false)
+
+  async function fetchInvoices() {
+    loading.value = true
+    try {
+      invoices.value = await invoke<Invoice[]>('get_invoices')
+    } catch (error) {
+      console.error('Failed to fetch invoices:', error)
+    } finally {
+      loading.value = false
+    }
+  }
+
+  async function createInvoice(invoice: Invoice): Promise<number | null> {
+    try {
+      const id = await invoke<number>('create_invoice', { invoice })
+      invoices.value.unshift({ ...invoice, id: Number(id) })
+      return Number(id)
+    } catch (error) {
+      console.error('Failed to create invoice:', error)
+      return null
+    }
+  }
+
+  async function updateInvoice(invoice: Invoice): Promise<boolean> {
+    try {
+      await invoke('update_invoice', { invoice })
+      const index = invoices.value.findIndex(i => i.id === invoice.id)
+      if (index !== -1) {
+        invoices.value[index] = invoice
+      }
+      return true
+    } catch (error) {
+      console.error('Failed to update invoice:', error)
+      return false
+    }
+  }
+
+  async function updateInvoiceTemplate(id: number, templateId: string): Promise<boolean> {
+    try {
+      await invoke('update_invoice_template', { id, templateId })
+      const index = invoices.value.findIndex(i => i.id === id)
+      if (index !== -1) {
+        invoices.value[index].template_id = templateId
+      }
+      return true
+    } catch (error) {
+      console.error('Failed to update invoice template:', error)
+      return false
+    }
+  }
+
+  async function deleteInvoice(id: number): Promise<boolean> {
+    try {
+      await invoke('delete_invoice', { id })
+      invoices.value = invoices.value.filter(i => i.id !== id)
+      return true
+    } catch (error) {
+      console.error('Failed to delete invoice:', error)
+      return false
+    }
+  }
+
+  async function getInvoiceItems(invoiceId: number): Promise<InvoiceItem[]> {
+    try {
+      return await invoke<InvoiceItem[]>('get_invoice_items', { invoiceId })
+    } catch (error) {
+      console.error('Failed to fetch invoice items:', error)
+      return []
+    }
+  }
+
+  async function createInvoiceItem(item: InvoiceItem): Promise<number | null> {
+    try {
+      return await invoke<number>('create_invoice_item', { item })
+    } catch (error) {
+      console.error('Failed to create invoice item:', error)
+      return null
+    }
+  }
+
+  async function saveInvoiceItems(invoiceId: number, items: { description: string; quantity: number; unit_price: number }[]): Promise<void> {
+    for (const item of items) {
+      await createInvoiceItem({
+        invoice_id: invoiceId,
+        description: item.description,
+        quantity: item.quantity,
+        rate: item.unit_price,
+        amount: item.quantity * item.unit_price,
+      })
+    }
+  }
+
+  return {
+    invoices,
+    loading,
+    fetchInvoices,
+    createInvoice,
+    updateInvoice,
+    updateInvoiceTemplate,
+    deleteInvoice,
+    getInvoiceItems,
+    createInvoiceItem,
+    saveInvoiceItems
+  }
+})