diff --git a/app/views/customer_appointments/_form.html.erb b/app/views/customer_appointments/_form.html.erb
index 9083a99..e6e485c 100644
--- a/app/views/customer_appointments/_form.html.erb
+++ b/app/views/customer_appointments/_form.html.erb
@@ -1,3 +1,5 @@
+<%= javascript_include_tag("customer-modal", plugin: :redmine_qbo_calendar) %>
+
 <%= labelled_form_for @appointment do |f| %>
   <%= error_messages_for @appointment %>
 
@@ -7,6 +9,8 @@
     <p>
       <%= f.text_field :customer, label: :label_customer, class: "customer-name", autocomplete: "off", data: { autocomplete_url: "/customers/autocomplete" } %>
       <%= f.hidden_field :customer_id, id: "customer_id" %>
+      <!-- Add Quick Create Button -->
+      <a href="#" id="inline-create-customer-btn" class="icon icon-add" title="New Customer">+</a>
     </p>
 
     <p>
@@ -42,4 +46,9 @@
   </div>
 
   <%= submit_tag l(:button_save) %>
-<% end %>
\ No newline at end of file
+<% end %>
+
+<!-- Modal Container for Inline Customer Creation -->
+<div id="new-customer-dialog" style="display:none;" title="<%= t(:label_new_customer, default: 'New Customer') %>">
+  <!-- The form will be dynamically loaded via JS or rendered here -->
+</div>
\ No newline at end of file
diff --git a/assets/javascripts/customer-modal.js b/assets/javascripts/customer-modal.js
new file mode 100644
index 0000000..1635d9c
--- /dev/null
+++ b/assets/javascripts/customer-modal.js
@@ -0,0 +1,106 @@
+$(document).ready(function() {
+  var $dialog = $('#new-customer-dialog');
+  var customerFormXHR = null;
+
+  // 1. Initialize jQuery UI Dialog (built into Redmine)
+  $dialog.dialog({
+    autoOpen: false,
+    modal: true,
+    width: 500,
+    title: "New Customer",
+    buttons: {
+      "Save": function() {
+        submitInlineCustomer();
+      },
+      "Cancel": function() {
+        $(this).dialog("close");
+      }
+    },
+    close: function() {
+      // Abort in-flight request if closing before load finishes
+      if (customerFormXHR) {
+        customerFormXHR.abort();
+      }
+      // Force hide Redmine's global loading overlay
+      $('#ajax-indicator').hide();
+      // Reset modal contents
+      $dialog.empty();
+    }
+  });
+
+  // 2. Open Modal & Fetch Form
+  $('#inline-create-customer-btn').on('click', function(e) {
+    e.preventDefault();
+
+    // Explicitly grab value by the appointment field's specific ID
+    var typedName = $('#customer_appointment_customer').val();
+
+    $dialog.dialog('open');
+
+    // Fetch form bypassing Redmine's global ajax-indicator
+    customerFormXHR = $.ajax({
+      url: '/customers/new',
+      type: 'GET',
+      global: false,
+      success: function(data) {
+        $dialog.html(data);
+
+        // Hide standalone submit button and wiki toolbar inside modal
+        $dialog.find('.actions, .jstBlock').hide();
+
+        // Copy typed name into the modal's specific customer_name field
+        if (typedName && typedName.trim() !== '') {
+          $dialog.find('#customer_name').val(typedName.trim());
+        }
+
+        // Handle ENTER key submission inside modal form
+        $dialog.find('form').off('submit').on('submit', function(ev) {
+          ev.preventDefault();
+          submitInlineCustomer();
+        });
+      },
+      error: function(xhr, status) {
+        if (status !== 'abort') {
+          $dialog.html('<p style="color: red; padding: 10px;">Failed to load customer form.</p>');
+        }
+      }
+    });
+  });
+
+  // 3. Submit Customer Form via AJAX
+  function submitInlineCustomer() {
+    var $form = $dialog.find('form');
+    if ($form.length === 0) return;
+
+    $.ajax({
+      url: $form.attr('action'),
+      type: 'POST',
+      data: $form.serialize(),
+      dataType: 'json',
+      global: false,
+      success: function(response) {
+        // Populate main appointment form fields with newly created customer details
+        $('#customer_id').val(response.id);
+        $('#customer_appointment_customer').val(response.name);
+
+        // Reset dependent select dropdowns for new customer
+        $('#appointment_vehicle_id').empty().append('<option value=""></option>');
+        $('#appointment_estimate_id').empty().append('<option value=""></option>');
+
+        // Close and clean up modal
+        $dialog.dialog('close');
+      },
+      error: function(xhr) {
+        var errors = (xhr.responseJSON && xhr.responseJSON.errors) 
+          ? xhr.responseJSON.errors 
+          : ['Failed to create customer'];
+        alert("Errors:\n" + errors.join("\n"));
+      }
+    });
+  }
+
+  // 4. Dismiss Redmine's global loader when selecting from autocomplete
+  $(document).on('autocompleteselect', '.customer-name', function(event, ui) {
+    $('#ajax-indicator').hide();
+  });
+});
\ No newline at end of file