diff --git a/frontend/components.d.ts b/frontend/components.d.ts
index 984d8e3a..84f74933 100644
--- a/frontend/components.d.ts
+++ b/frontend/components.d.ts
@@ -162,7 +162,11 @@ declare module 'vue' {
     ListIcon: typeof import('./src/components/Icons/ListIcon.vue')['default']
     ListRows: typeof import('./src/components/ListViews/ListRows.vue')['default']
     LoadingIndicator: typeof import('./src/components/Icons/LoadingIndicator.vue')['default']
+<<<<<<< HEAD
     LucideCalendar: typeof import('~icons/lucide/calendar')['default']
+=======
+    LostReasonModal: typeof import('./src/components/Modals/LostReasonModal.vue')['default']
+>>>>>>> d89c304b (fix: show lost reason modal if status changed to lost)
     LucideInfo: typeof import('~icons/lucide/info')['default']
     LucideMoreHorizontal: typeof import('~icons/lucide/more-horizontal')['default']
     LucidePlus: typeof import('~icons/lucide/plus')['default']
diff --git a/frontend/src/components/Modals/LostReasonModal.vue b/frontend/src/components/Modals/LostReasonModal.vue
new file mode 100644
index 00000000..7553641d
--- /dev/null
+++ b/frontend/src/components/Modals/LostReasonModal.vue
@@ -0,0 +1,99 @@
+<template>
+  <Dialog
+    v-model="show"
+    :options="{ title: __('Lost reason') }"
+    @close="cancel"
+  >
+    <template #body-content>
+      <div class="-mt-3 mb-4 text-p-base text-ink-gray-7">
+        {{ __('Please provide a reason for marking this deal as lost') }}
+      </div>
+      <div class="flex flex-col gap-3">
+        <div>
+          <div class="mb-2 text-sm text-ink-gray-5">
+            {{ __('Lost reason') }}
+            <span class="text-ink-red-2">*</span>
+          </div>
+          <Link
+            class="form-control flex-1 truncate"
+            :value="lostReason"
+            doctype="CRM Lost Reason"
+            @change="(v) => (lostReason = v)"
+            :onCreate="onCreate"
+          />
+        </div>
+        <div>
+          <div class="mb-2 text-sm text-ink-gray-5">
+            {{ __('Lost notes') }}
+            <span v-if="lostReason == 'Other'" class="text-ink-red-2">*</span>
+          </div>
+          <FormControl
+            class="form-control flex-1 truncate"
+            type="textarea"
+            :value="lostNotes"
+            @change="(e) => (lostNotes = e.target.value)"
+          />
+        </div>
+      </div>
+    </template>
+    <template #actions>
+      <div class="flex justify-between items-center gap-2">
+        <div><ErrorMessage :message="error" /></div>
+        <div class="flex gap-2">
+          <Button :label="__('Cancel')" @click="cancel" />
+          <Button variant="solid" :label="__('Save')" @click="save" />
+        </div>
+      </div>
+    </template>
+  </Dialog>
+</template>
+<script setup>
+import Link from '@/components/Controls/Link.vue'
+import { Dialog } from 'frappe-ui'
+import { ref } from 'vue'
+
+const props = defineProps({
+  deal: {
+    type: Object,
+    required: true,
+  },
+})
+
+const show = defineModel()
+
+const lostReason = ref('')
+const lostNotes = ref('')
+const error = ref('')
+
+function cancel() {
+  show.value = false
+  error.value = ''
+  lostReason.value = ''
+  lostNotes.value = ''
+  props.deal.doc.status = props.deal.originalDoc.status
+}
+
+function save() {
+  if (!lostReason.value) {
+    error.value = __('Lost reason is required')
+    return
+  }
+  if (lostReason.value === 'Other' && !lostNotes.value) {
+    error.value = __('Lost notes are required when lost reason is "Other"')
+    return
+  }
+
+  error.value = ''
+  show.value = false
+
+  props.deal.doc.lost_reason = lostReason.value
+  props.deal.doc.lost_notes = lostNotes.value
+  props.deal.save.submit()
+}
+
+function onCreate() {
+  // This function can be used to handle the creation of a new lost reason
+  // For now, we just close the modal after creating a new reason
+  show.value = false
+}
+</script>
diff --git a/frontend/src/pages/Deal.vue b/frontend/src/pages/Deal.vue
index baaf0a53..3efb5b0e 100644
--- a/frontend/src/pages/Deal.vue
+++ b/frontend/src/pages/Deal.vue
@@ -327,6 +327,11 @@
     :docname="props.dealId"
     name="Deals"
   />
+  <LostReasonModal
+    v-if="showLostReasonModal"
+    v-model="showLostReasonModal"
+    :deal="document"
+  />
 </template>
 <script setup>
 import ErrorPage from '@/components/ErrorPage.vue'
@@ -350,6 +355,7 @@ import AttachmentIcon from '@/components/Icons/AttachmentIcon.vue'
 import LayoutHeader from '@/components/LayoutHeader.vue'
 import Activities from '@/components/Activities/Activities.vue'
 import OrganizationModal from '@/components/Modals/OrganizationModal.vue'
+import LostReasonModal from '@/components/Modals/LostReasonModal.vue'
 import AssignTo from '@/components/AssignTo.vue'
 import FilesUploader from '@/components/FilesUploader/FilesUploader.vue'
 import ContactModal from '@/components/Modals/ContactModal.vue'
@@ -758,7 +764,22 @@ const { assignees, document, triggerOnChange } = useDocument(
 
 async function triggerStatusChange(value) {
   await triggerOnChange('status', value)
-  document.save.submit()
+  setLostReason()
+}
+
+const showLostReasonModal = ref(false)
+
+function setLostReason() {
+  if (
+    document.doc.status !== 'Lost' ||
+    (document.doc.lost_reason && document.doc.lost_reason !== 'Other') ||
+    (document.doc.lost_reason === 'Other' && document.doc.lost_notes)
+  ) {
+    document.save.submit()
+    return
+  }
+
+  showLostReasonModal.value = true
 }
 
 function reloadAssignees(data) {
diff --git a/frontend/src/pages/MobileDeal.vue b/frontend/src/pages/MobileDeal.vue
index 1039b387..c8355bd1 100644
--- a/frontend/src/pages/MobileDeal.vue
+++ b/frontend/src/pages/MobileDeal.vue
@@ -245,6 +245,11 @@
       afterInsert: (doc) => addContact(doc.name),
     }"
   />
+  <LostReasonModal
+    v-if="showLostReasonModal"
+    v-model="showLostReasonModal"
+    :deal="document"
+  />
 </template>
 <script setup>
 import Icon from '@/components/Icon.vue'
@@ -265,6 +270,7 @@ import SuccessIcon from '@/components/Icons/SuccessIcon.vue'
 import LayoutHeader from '@/components/LayoutHeader.vue'
 import Activities from '@/components/Activities/Activities.vue'
 import OrganizationModal from '@/components/Modals/OrganizationModal.vue'
+import LostReasonModal from '@/components/Modals/LostReasonModal.vue'
 import AssignTo from '@/components/AssignTo.vue'
 import ContactModal from '@/components/Modals/ContactModal.vue'
 import Section from '@/components/Section.vue'
@@ -627,7 +633,22 @@ const { assignees, document, triggerOnChange } = useDocument(
 
 async function triggerStatusChange(value) {
   await triggerOnChange('status', value)
-  document.save.submit()
+  setLostReason()
+}
+
+const showLostReasonModal = ref(false)
+
+function setLostReason() {
+  if (
+    document.doc.status !== 'Lost' ||
+    (document.doc.lost_reason && document.doc.lost_reason !== 'Other') ||
+    (document.doc.lost_reason === 'Other' && document.doc.lost_notes)
+  ) {
+    document.save.submit()
+    return
+  }
+
+  showLostReasonModal.value = true
 }
 
 function reloadAssignees(data) {