diff --git a/i18n/core/en.json b/i18n/core/en.json
index f0b95562..bce90285 100644
--- a/i18n/core/en.json
+++ b/i18n/core/en.json
@@ -21,6 +21,7 @@
     "deputy.session.section.close": "Archive section",
     "deputy.session.section.closeComments": "Archiving comments",
     "deputy.session.section.closeHelp": "Your signature will automatically be included.",
+    "deputy.session.section.closeWarning": "Some revisions remain unassessed. You may want to mark these revisions as assessed before archiving this section.",
     "deputy.session.section.closeWarn": "You have unsaved changes. Close the section without saving?",
 
     "deputy.session.section.stop": "Stop session",
diff --git a/src/css/deputy.css b/src/css/deputy.css
index f0e8a825..17b46889 100644
--- a/src/css/deputy.css
+++ b/src/css/deputy.css
@@ -265,6 +265,10 @@ body.mediawiki.rtl .dp-cs-row-head > :not(:first-child):not(:last-child) {
 	margin-bottom: 8px;
 }
 
+.dp-cs-section-unfinishedWarning {
+	margin-top: 8px;
+}
+
 .dp-cs-row-closeComments {
 	font-family: monospace, monospace;
 	font-size: small;
diff --git a/src/ui/root/DeputyContributionSurveyRow.tsx b/src/ui/root/DeputyContributionSurveyRow.tsx
index 12e8d011..b4eeb3bf 100644
--- a/src/ui/root/DeputyContributionSurveyRow.tsx
+++ b/src/ui/root/DeputyContributionSurveyRow.tsx
@@ -517,7 +517,7 @@ export default class DeputyContributionSurveyRow implements DeputyUIElement {
 
 		this.unfinishedMessageBox = new OO.ui.MessageWidget( {
 			classes: [ 'dp-cs-row-unfinishedWarning' ],
-			type: 'warn',
+			type: 'warning',
 			label: mw.msg( 'deputy.session.row.unfinishedWarning' )
 		} );
 		this.unfinishedMessageBox.toggle( false );
diff --git a/src/ui/root/DeputyContributionSurveySection.tsx b/src/ui/root/DeputyContributionSurveySection.tsx
index eefd1027..590a5ec8 100644
--- a/src/ui/root/DeputyContributionSurveySection.tsx
+++ b/src/ui/root/DeputyContributionSurveySection.tsx
@@ -18,6 +18,7 @@ import {
 	ContributionSurveyRowSigningBehavior
 } from '../../models/ContributionSurveyRowSigningBehavior';
 import { generateTrace } from '../../models/DeputyTrace';
+import DeputyMessageWidget from '../shared/DeputyMessageWidget';
 
 /**
  * The contribution survey section UI element. This includes a list of revisions
@@ -519,6 +520,13 @@ export default class DeputyContributionSurveySection implements DeputyUIElement
 			this.setDisabled( false );
 		} );
 
+		const closingWarning = DeputyMessageWidget( {
+			classes: [ 'dp-cs-section-unfinishedWarning' ],
+			type: 'warning',
+			label: mw.msg( 'deputy.session.section.closeWarning' )
+		} );
+		closingWarning.toggle( false );
+
 		const closingCommentsField = new OO.ui.FieldLayout( this.closingComments, {
 			align: 'top',
 			label: 'Closing comments',
@@ -537,6 +545,7 @@ export default class DeputyContributionSurveySection implements DeputyUIElement
 		this.closingCheckbox.on( 'change', ( v: boolean ) => {
 			this.closed = v;
 			closingCommentsField.toggle( v );
+			closingWarning.toggle( v && this.rows.some( ( row ) => !row.completed ) );
 			this.toggleClosingComments( v );
 		} );
 		this.closingComments.on( 'change', ( v: string ) => {
@@ -561,6 +570,7 @@ export default class DeputyContributionSurveySection implements DeputyUIElement
 							align: 'inline',
 							label: mw.msg( 'deputy.session.section.close' )
 						} ) ) }
+						{ unwrapWidget( closingWarning ) }
 						{ unwrapWidget( closingCommentsField ) }
 					</div>
 					<div style={{ display: 'flex', alignItems: 'end' }}>