diff --git a/browser/ui/webui/brave_webui_source.cc b/browser/ui/webui/brave_webui_source.cc
index de1d8e46f90c..a237b6d574c9 100644
--- a/browser/ui/webui/brave_webui_source.cc
+++ b/browser/ui/webui/brave_webui_source.cc
@@ -445,6 +445,7 @@ void CustomizeWebUIHTMLSource(const std::string &name, content::WebUIDataSource*
         { "wordCount",  IDS_BRAVE_SYNC_SHARED_WORD_COUNT_TEXT },
         { "ok", IDS_BRAVE_SYNC_SHARED_OK_BUTTON },
         { "cancel", IDS_BRAVE_SYNC_SHARED_CANCEL_BUTTON },
+        { "cancelDeviceSyncing", IDS_BRAVE_SYNC_SHARED_CANCEL_SYNCING },
         { "thisSyncChain", IDS_BRAVE_SYNC_SHARED_FROM_THIS_CHAIN_PARTIAL },
         { "lookingForDevice", IDS_BRAVE_SYNC_SCAN_CODE_LOOKING_FOR_DEVICE_BUTTON },
         { "viewSyncCode", IDS_BRAVE_SYNC_ENABLED_VIEW_CODE_BUTTON },
diff --git a/components/brave_sync/ui/components/commonDialogs/cancelDeviceSyncing.tsx b/components/brave_sync/ui/components/commonDialogs/cancelDeviceSyncing.tsx
new file mode 100644
index 000000000000..251478bc1a19
--- /dev/null
+++ b/components/brave_sync/ui/components/commonDialogs/cancelDeviceSyncing.tsx
@@ -0,0 +1,36 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import * as React from 'react'
+
+// Components
+import { AlertBox } from 'brave-ui'
+
+// Feature-specific components
+import { Title, Paragraph } from 'brave-ui/features/sync'
+
+// Utils
+import { getLocale } from '../../../../common/locale'
+
+interface Props {
+  onClickOk: () => void
+  onClickCancel: () => void
+}
+
+export default class AreYouSure extends React.PureComponent<Props, {}> {
+  render () {
+    const { onClickOk, onClickCancel } = this.props
+    return (
+      <AlertBox
+        okString={getLocale('ok')}
+        onClickOk={onClickOk}
+        cancelString={getLocale('cancel')}
+        onClickCancel={onClickCancel}
+      >
+        <Title level={1}>{getLocale('areYouSure')}</Title>
+        <Paragraph>{getLocale('cancelDeviceSyncing')}</Paragraph>
+      </AlertBox>
+    )
+  }
+}
diff --git a/components/brave_sync/ui/components/modals/scanCode.tsx b/components/brave_sync/ui/components/modals/scanCode.tsx
index a3e3c66c9bef..6ddc3de6392e 100644
--- a/components/brave_sync/ui/components/modals/scanCode.tsx
+++ b/components/brave_sync/ui/components/modals/scanCode.tsx
@@ -19,6 +19,9 @@ import {
   Link
 } from 'brave-ui/features/sync'
 
+// Dialogs
+import CancelDeviceSyncingDialog from '../commonDialogs/cancelDeviceSyncing'
+
 // Utils
 import { getLocale } from '../../../../common/locale'
 
@@ -30,7 +33,16 @@ interface Props {
   actions: any
 }
 
-export default class ScanCodeModal extends React.PureComponent<Props, {}> {
+interface State {
+  willCancelScanCode: boolean
+}
+
+export default class ScanCodeModal extends React.PureComponent<Props, State> {
+  constructor (props: Props) {
+    super(props)
+    this.state = { willCancelScanCode: false }
+  }
+
   componentDidMount () {
     const { scanCode, deviceType } = this.props.syncData.modalsOpen
     if (scanCode) {
@@ -46,6 +58,19 @@ export default class ScanCodeModal extends React.PureComponent<Props, {}> {
   }
 
   onDismissModal = () => {
+    const { devices, isSyncConfigured } = this.props.syncData
+    // if user is still trying to build a sync chain,
+    // open the confirmation modal. otherwise close it
+    isSyncConfigured && devices.length < 2
+      ? this.setState({ willCancelScanCode: true })
+      : this.props.actions.maybeOpenSyncModal('scanCode', false)
+  }
+
+  onDismissDialog = () => {
+    this.setState({ willCancelScanCode: false })
+  }
+
+  onConfirmDismissModal = () => {
     const { devices, isSyncConfigured } = this.props.syncData
     // sync is enabled when at least 2 devices are in the chain.
     // this modal works both with sync enabled and disabled states.
@@ -54,14 +79,20 @@ export default class ScanCodeModal extends React.PureComponent<Props, {}> {
     if (isSyncConfigured && devices.length < 2) {
       this.props.actions.onSyncReset()
     }
+    this.setState({ willCancelScanCode: false })
     this.props.actions.maybeOpenSyncModal('scanCode', false)
   }
 
   render () {
     const { syncData } = this.props
+    const { willCancelScanCode } = this.state
 
     return (
       <Modal id='scanCodeModal' displayCloseButton={false} size='small'>
+        {
+          willCancelScanCode &&
+          <CancelDeviceSyncingDialog onClickCancel={this.onDismissDialog} onClickOk={this.onConfirmDismissModal} />
+        }
         <ModalHeader>
           <div>
             <Title level={1}>{getLocale('scanThisCode')}</Title>
diff --git a/components/brave_sync/ui/components/modals/viewSyncCode.tsx b/components/brave_sync/ui/components/modals/viewSyncCode.tsx
index 5593a64d1dbe..5f2b1b85a504 100644
--- a/components/brave_sync/ui/components/modals/viewSyncCode.tsx
+++ b/components/brave_sync/ui/components/modals/viewSyncCode.tsx
@@ -18,6 +18,9 @@ import {
   Link
 } from 'brave-ui/features/sync'
 
+// Dialogs
+import CancelDeviceSyncingDialog from '../commonDialogs/cancelDeviceSyncing'
+
 // Utils
 import { getLocale } from '../../../../common/locale'
 
@@ -26,7 +29,16 @@ interface Props {
   actions: any
 }
 
-export default class ViewSyncCodeModal extends React.PureComponent<Props, {}> {
+interface State {
+  willCancelViewCode: boolean
+}
+
+export default class ViewSyncCodeModal extends React.PureComponent<Props, State> {
+  constructor (props: Props) {
+    super(props)
+    this.state = { willCancelViewCode: false }
+  }
+
   componentDidMount () {
     const { scanCode, deviceType } = this.props.syncData.modalsOpen
     if (scanCode) {
@@ -42,6 +54,19 @@ export default class ViewSyncCodeModal extends React.PureComponent<Props, {}> {
   }
 
   onDismissModal = () => {
+    const { devices, isSyncConfigured } = this.props.syncData
+    // if user is still trying to build a sync chain,
+    // open the confirmation modal. otherwise close it
+    isSyncConfigured && devices.length < 2
+      ? this.setState({ willCancelViewCode: true })
+      : this.props.actions.maybeOpenSyncModal('viewSyncCode', false)
+  }
+
+  onDismissDialog = () => {
+    this.setState({ willCancelViewCode: false })
+  }
+
+  onConfirmDismissModal = () => {
     const { devices, isSyncConfigured } = this.props.syncData
     // sync is enabled when at least 2 devices are in the chain.
     // this modal works both with sync enabled and disabled states.
@@ -50,14 +75,20 @@ export default class ViewSyncCodeModal extends React.PureComponent<Props, {}> {
     if (isSyncConfigured && devices.length < 2) {
       this.props.actions.onSyncReset()
     }
+    this.setState({ willCancelViewCode: false })
     this.props.actions.maybeOpenSyncModal('viewSyncCode', false)
   }
 
   render () {
     const { syncData } = this.props
+    const { willCancelViewCode } = this.state
 
     return (
       <Modal id='viewSyncCodeModal' displayCloseButton={false} size='small'>
+        {
+          willCancelViewCode &&
+          <CancelDeviceSyncingDialog onClickCancel={this.onDismissDialog} onClickOk={this.onConfirmDismissModal} />
+        }
         <ModalHeader>
           <div>
             <Title level={1}>{getLocale('chainCode')}</Title>
diff --git a/components/resources/brave_components_strings.grd b/components/resources/brave_components_strings.grd
index c447e3257aca..5cc5dc80e35e 100644
--- a/components/resources/brave_components_strings.grd
+++ b/components/resources/brave_components_strings.grd
@@ -454,6 +454,7 @@
       <message name="IDS_BRAVE_SYNC_SHARED_WORD_COUNT_TEXT" desc="The Sync `word count` phrase that shows how many words are in a textarea field">Word Count:</message>
       <message name="IDS_BRAVE_SYNC_SHARED_OK_BUTTON" desc="The Sync `ok` button that indicates user is aware of what is being written">Ok</message>
       <message name="IDS_BRAVE_SYNC_SHARED_CANCEL_BUTTON" desc="The Sync `cancel` button that closes the current modal">Cancel</message>
+      <message name="IDS_BRAVE_SYNC_SHARED_CANCEL_SYNCING" desc="The Sync phrase for when the user is about to reset sync by closing the `view code` or `scan code` modal">Cancelling this modal will reset the current chain and the devices looking for this code would not be able to sync with this computer.</message>
       <message name="IDS_BRAVE_SYNC_SHARED_FROM_THIS_CHAIN_PARTIAL" desc="The Sync partial phrase included in `remove X from this sync chain` where X is the user's device name">from this sync chain</message>
       <message name="IDS_BRAVE_SYNC_SHARED_VIEW_CODE_BUTTON" desc="The Sync button to enter code words instead of scanning the current code">View Code Words</message>
       <message name="IDS_BRAVE_SYNC_SCAN_CODE_LOOKING_FOR_DEVICE_BUTTON" desc="The Sync temporary button that holds while a device is not found yet">Looking for device</message>