diff --git a/packages/@lwc/template-compiler/src/parser/constants.ts b/packages/@lwc/template-compiler/src/parser/constants.ts
index 560e80f795..124de5d2bd 100644
--- a/packages/@lwc/template-compiler/src/parser/constants.ts
+++ b/packages/@lwc/template-compiler/src/parser/constants.ts
@@ -162,3 +162,6 @@ export const ATTR_NAME = {
     XLINK_HREF: 'xlink:href',
 };
 export const TEMPLATE_DIRECTIVES = [/^key$/, /^lwc:*/, /^if:*/, /^for:*/, /^iterator:*/];
+
+// TODO [#3370]: remove experimental template expression flag
+export const TMPL_EXPR_ECMASCRIPT_EDITION = 2022;
diff --git a/packages/@lwc/template-compiler/src/parser/expression-complex/html.ts b/packages/@lwc/template-compiler/src/parser/expression-complex/html.ts
index 00e2152b67..d09810eae9 100644
--- a/packages/@lwc/template-compiler/src/parser/expression-complex/html.ts
+++ b/packages/@lwc/template-compiler/src/parser/expression-complex/html.ts
@@ -10,6 +10,7 @@ import { Document, DocumentFragment, ParsingError, ParserOptions } from 'parse5'
 import { ParserDiagnostics, invariant } from '@lwc/errors';
 import Parser from 'parse5/lib/parser';
 import Tokenizer from 'parse5/lib/tokenizer';
+import { TMPL_EXPR_ECMASCRIPT_EDITION } from '../constants';
 import type ParserCtx from '../parser';
 import type { PreparsedExpressionMap } from './types';
 
@@ -55,7 +56,7 @@ class TemplateHtmlTokenizer extends Tokenizer {
 
         // Start parsing immediately after the opening curly brace.
         const estreeNode = parseExpressionAt(html, javascriptExprStart, {
-            ecmaVersion: 2022,
+            ecmaVersion: TMPL_EXPR_ECMASCRIPT_EDITION,
             locations: true,
             ranges: true,
             onComment: () => invariant(false, ParserDiagnostics.INVALID_EXPR_COMMENTS_DISALLOWED),
diff --git a/packages/@lwc/template-compiler/src/parser/expression.ts b/packages/@lwc/template-compiler/src/parser/expression.ts
index f4cdb2221e..692d7f6f59 100644
--- a/packages/@lwc/template-compiler/src/parser/expression.ts
+++ b/packages/@lwc/template-compiler/src/parser/expression.ts
@@ -11,6 +11,7 @@ import * as t from '../shared/estree';
 import { NormalizedConfig } from '../config';
 import { Expression, Identifier, SourceLocation } from '../shared/types';
 import { validateExpressionAst } from './expression-complex';
+import { TMPL_EXPR_ECMASCRIPT_EDITION } from './constants';
 
 import ParserCtx from './parser';
 import { isReservedES6Keyword } from './utils/javascript';
@@ -103,7 +104,9 @@ export function parseExpression(
     source: string,
     location: SourceLocation
 ): Expression {
-    const ecmaVersion = ctx.config.experimentalComplexExpressions ? 2022 : 2020;
+    const ecmaVersion = ctx.config.experimentalComplexExpressions
+        ? TMPL_EXPR_ECMASCRIPT_EDITION
+        : 2020;
     return ctx.withErrorWrapping(
         () => {
             const parsed = parseExpressionAt(source, 1, { ecmaVersion });