diff --git a/src/vs/editor/common/modes.ts b/src/vs/editor/common/modes.ts
index 78610e6c004..7060c53fdfc 100644
--- a/src/vs/editor/common/modes.ts
+++ b/src/vs/editor/common/modes.ts
@@ -867,6 +867,9 @@ export const enum SymbolKind {
 	TypeParameter = 25
 }
 
+export const enum SymbolKindTag {
+	Deprecated = 1,
+}
 
 /**
  * @internal
@@ -910,6 +913,7 @@ export interface DocumentSymbol {
 	name: string;
 	detail: string;
 	kind: SymbolKind;
+	kindTags: SymbolKindTag[];
 	containerName?: string;
 	range: IRange;
 	selectionRange: IRange;
diff --git a/src/vs/editor/common/standalone/standaloneEnums.ts b/src/vs/editor/common/standalone/standaloneEnums.ts
index 76ee0d96933..4aa60848562 100644
--- a/src/vs/editor/common/standalone/standaloneEnums.ts
+++ b/src/vs/editor/common/standalone/standaloneEnums.ts
@@ -660,4 +660,8 @@ export enum SymbolKind {
 	Event = 23,
 	Operator = 24,
 	TypeParameter = 25
+}
+
+export enum SymbolKindTag {
+	Deprecated = 1
 }
\ No newline at end of file
diff --git a/src/vs/editor/contrib/documentSymbols/media/outlineTree.css b/src/vs/editor/contrib/documentSymbols/media/outlineTree.css
index ebc2389a0e2..3d6454a1556 100644
--- a/src/vs/editor/contrib/documentSymbols/media/outlineTree.css
+++ b/src/vs/editor/contrib/documentSymbols/media/outlineTree.css
@@ -20,6 +20,11 @@
 	color: var(--outline-element-color);
 }
 
+.monaco-list .outline-element .deprecated {
+	text-decoration: line-through;
+	opacity: 0.66;
+}
+
 .monaco-tree .monaco-tree-row.focused .outline-element .outline-element-detail {
 	visibility: inherit;
 }
diff --git a/src/vs/editor/contrib/documentSymbols/outlineTree.ts b/src/vs/editor/contrib/documentSymbols/outlineTree.ts
index 365b3e45c13..6df7d87e2ee 100644
--- a/src/vs/editor/contrib/documentSymbols/outlineTree.ts
+++ b/src/vs/editor/contrib/documentSymbols/outlineTree.ts
@@ -12,7 +12,7 @@ import { createMatches, FuzzyScore } from 'vs/base/common/filters';
 import 'vs/css!./media/outlineTree';
 import 'vs/css!./media/symbol-icons';
 import { Range } from 'vs/editor/common/core/range';
-import { SymbolKind, symbolKindToCssClass } from 'vs/editor/common/modes';
+import { SymbolKind, symbolKindToCssClass, SymbolKindTag } from 'vs/editor/common/modes';
 import { OutlineElement, OutlineGroup, OutlineModel } from 'vs/editor/contrib/documentSymbols/outlineModel';
 import { localize } from 'vs/nls';
 import { IconLabel } from 'vs/base/browser/ui/iconLabel/iconLabel';
@@ -127,6 +127,10 @@ export class OutlineElementRenderer implements ITreeRenderer<OutlineElement, Fuz
 			// add styles for the icons
 			options.extraClasses.push(`outline-element-icon ${symbolKindToCssClass(element.symbol.kind, true)}`);
 		}
+		if (element.symbol.kindTags.indexOf(SymbolKindTag.Deprecated) >= 0) {
+			options.extraClasses.push(`deprecated`);
+			options.matches = [];
+		}
 		template.iconLabel.setLabel(element.symbol.name, element.symbol.detail, options);
 		this._renderMarkerInfo(element, template);
 	}
diff --git a/src/vs/editor/contrib/documentSymbols/test/outlineModel.test.ts b/src/vs/editor/contrib/documentSymbols/test/outlineModel.test.ts
index b15a1451072..9622de2716e 100644
--- a/src/vs/editor/contrib/documentSymbols/test/outlineModel.test.ts
+++ b/src/vs/editor/contrib/documentSymbols/test/outlineModel.test.ts
@@ -76,6 +76,7 @@ suite('OutlineModel', function () {
 			name,
 			detail: 'fake',
 			kind: SymbolKind.Boolean,
+			kindTags: [],
 			selectionRange: range,
 			range: range
 		};
diff --git a/src/vs/editor/contrib/quickOpen/quickOpen.ts b/src/vs/editor/contrib/quickOpen/quickOpen.ts
index dba67c40b01..919e3eae792 100644
--- a/src/vs/editor/contrib/quickOpen/quickOpen.ts
+++ b/src/vs/editor/contrib/quickOpen/quickOpen.ts
@@ -51,6 +51,7 @@ function flatten(bucket: DocumentSymbol[], entries: DocumentSymbol[], overrideCo
 	for (let entry of entries) {
 		bucket.push({
 			kind: entry.kind,
+			kindTags: [],
 			name: entry.name,
 			detail: entry.detail,
 			containerName: entry.containerName || overrideContainerLabel,
diff --git a/src/vs/editor/standalone/browser/standaloneLanguages.ts b/src/vs/editor/standalone/browser/standaloneLanguages.ts
index 30209af005c..0576af462b1 100644
--- a/src/vs/editor/standalone/browser/standaloneLanguages.ts
+++ b/src/vs/editor/standalone/browser/standaloneLanguages.ts
@@ -565,6 +565,7 @@ export function createMonacoLanguagesAPI(): typeof monaco.languages {
 		CompletionItemKindModifier: standaloneEnums.CompletionItemKindModifier,
 		CompletionItemInsertTextRule: standaloneEnums.CompletionItemInsertTextRule,
 		SymbolKind: standaloneEnums.SymbolKind,
+		SymbolKindTag: standaloneEnums.SymbolKindTag,
 		IndentAction: standaloneEnums.IndentAction,
 		CompletionTriggerKind: standaloneEnums.CompletionTriggerKind,
 		SignatureHelpTriggerKind: standaloneEnums.SignatureHelpTriggerKind,
diff --git a/src/vs/monaco.d.ts b/src/vs/monaco.d.ts
index 5cab18f9cff..1d2b95c1694 100644
--- a/src/vs/monaco.d.ts
+++ b/src/vs/monaco.d.ts
@@ -5232,10 +5232,15 @@ declare namespace monaco.languages {
 		TypeParameter = 25
 	}
 
+	export enum SymbolKindTag {
+		Deprecated = 1
+	}
+
 	export interface DocumentSymbol {
 		name: string;
 		detail: string;
 		kind: SymbolKind;
+		kindTags: SymbolKindTag[];
 		containerName?: string;
 		range: IRange;
 		selectionRange: IRange;
diff --git a/src/vs/workbench/api/common/extHostLanguageFeatures.ts b/src/vs/workbench/api/common/extHostLanguageFeatures.ts
index 3954141c90a..a39d24d756a 100644
--- a/src/vs/workbench/api/common/extHostLanguageFeatures.ts
+++ b/src/vs/workbench/api/common/extHostLanguageFeatures.ts
@@ -70,6 +70,7 @@ class DocumentSymbolAdapter {
 			const element = <modes.DocumentSymbol>{
 				name: info.name || '!!MISSING: name!!',
 				kind: typeConvert.SymbolKind.from(info.kind),
+				kindTags: [],
 				detail: undefined!, // Strict null override — avoid changing behavior
 				containerName: info.containerName,
 				range: typeConvert.Range.from(info.location.range),
diff --git a/src/vs/workbench/api/common/extHostTypeConverters.ts b/src/vs/workbench/api/common/extHostTypeConverters.ts
index 1fdc6fef86f..0a3819ccd83 100644
--- a/src/vs/workbench/api/common/extHostTypeConverters.ts
+++ b/src/vs/workbench/api/common/extHostTypeConverters.ts
@@ -582,7 +582,8 @@ export namespace DocumentSymbol {
 			detail: info.detail,
 			range: Range.from(info.range),
 			selectionRange: Range.from(info.selectionRange),
-			kind: SymbolKind.from(info.kind)
+			kind: SymbolKind.from(info.kind),
+			kindTags: []
 		};
 		if (info.children) {
 			result.children = info.children.map(from);