diff --git a/its/ruling/src/test/expected/jsts/Joust/typescript-S6836.json b/its/ruling/src/test/expected/jsts/Joust/typescript-S6836.json
new file mode 100644
index 00000000000..83684a2e570
--- /dev/null
+++ b/its/ruling/src/test/expected/jsts/Joust/typescript-S6836.json
@@ -0,0 +1,24 @@
+{
+"Joust:ts/components/EventLogLine.tsx": [
+211
+],
+"Joust:ts/components/GameWrapper.tsx": [
+135,
+136
+],
+"Joust:ts/components/game/Player.tsx": [
+343
+],
+"Joust:ts/protocol/HSReplayDecoder.ts": [
+96,
+131,
+143,
+320,
+321,
+357
+],
+"Joust:ts/protocol/KettleDecoder.ts": [
+130,
+145
+]
+}
diff --git a/its/ruling/src/test/expected/jsts/TypeScript/typescript-S6836.json b/its/ruling/src/test/expected/jsts/TypeScript/typescript-S6836.json
new file mode 100644
index 00000000000..d59d1c2a4d7
--- /dev/null
+++ b/its/ruling/src/test/expected/jsts/TypeScript/typescript-S6836.json
@@ -0,0 +1,199 @@
+{
+"TypeScript:scripts/buildProtocol.ts": [
+86
+],
+"TypeScript:scripts/tslint/noIncrementDecrementRule.ts": [
+18
+],
+"TypeScript:src/compiler/binder.ts": [
+288,
+289,
+292,
+293,
+2026,
+2088,
+2089,
+2356,
+2357,
+2749,
+2750
+],
+"TypeScript:src/compiler/checker.ts": [
+921,
+3691,
+6652,
+7729,
+7990,
+8011,
+11410,
+11411,
+11412,
+15100,
+16593,
+16599,
+16996,
+17025,
+17073,
+17074,
+17674,
+17883,
+17884,
+18567,
+18568,
+18874,
+18875,
+18897,
+18898,
+18949,
+19017,
+21054,
+21065,
+21069,
+21095,
+21096,
+21097,
+21098,
+21146,
+21151,
+21380,
+21398,
+22036,
+22054,
+22323,
+22333,
+22341,
+22752,
+23311
+],
+"TypeScript:src/compiler/commandLineParser.ts": [
+792,
+804
+],
+"TypeScript:src/compiler/factory.ts": [
+2800
+],
+"TypeScript:src/compiler/parser.ts": [
+1696,
+1697,
+2526,
+6404,
+6425,
+6862
+],
+"TypeScript:src/compiler/program.ts": [
+1142,
+1161,
+1388
+],
+"TypeScript:src/compiler/scanner.ts": [
+650,
+651,
+1582
+],
+"TypeScript:src/compiler/transformers/es2015.ts": [
+1540,
+2657,
+3026
+],
+"TypeScript:src/compiler/transformers/es5.ts": [
+53
+],
+"TypeScript:src/compiler/transformers/ts.ts": [
+1804,
+1805,
+1861
+],
+"TypeScript:src/compiler/utilities.ts": [
+547,
+680,
+782,
+1271,
+1293,
+1299,
+1686,
+1692
+],
+"TypeScript:src/harness/harness.ts": [
+90,
+304
+],
+"TypeScript:src/server/scriptInfo.ts": [
+273
+],
+"TypeScript:src/server/server.ts": [
+454
+],
+"TypeScript:src/server/session.ts": [
+423,
+428,
+432
+],
+"TypeScript:src/server/utilities.ts": [
+44
+],
+"TypeScript:src/services/breakpoints.ts": [
+565,
+569,
+606,
+607,
+615,
+633
+],
+"TypeScript:src/services/codefixes/helpers.ts": [
+77,
+78,
+95,
+106
+],
+"TypeScript:src/services/codefixes/unusedIdentifierFixes.ts": [
+49,
+66,
+76,
+80,
+94,
+113,
+136,
+137,
+146,
+148,
+157
+],
+"TypeScript:src/services/completions.ts": [
+408,
+992
+],
+"TypeScript:src/services/documentHighlights.ts": [
+82
+],
+"TypeScript:src/services/formatting/formatting.ts": [
+177,
+1100,
+1111
+],
+"TypeScript:src/services/importTracker.ts": [
+105
+],
+"TypeScript:src/services/navigationBar.ts": [
+159,
+187,
+197,
+212,
+213,
+412
+],
+"TypeScript:src/services/outliningElementsCollector.ts": [
+168,
+169
+],
+"TypeScript:src/services/services.ts": [
+620,
+621,
+693,
+1378
+],
+"TypeScript:src/services/utilities.ts": [
+517,
+531,
+537
+]
+}
diff --git a/its/ruling/src/test/expected/jsts/ag-grid/typescript-S6836.json b/its/ruling/src/test/expected/jsts/ag-grid/typescript-S6836.json
new file mode 100644
index 00000000000..13ba3d664d0
--- /dev/null
+++ b/its/ruling/src/test/expected/jsts/ag-grid/typescript-S6836.json
@@ -0,0 +1,9 @@
+{
+"ag-grid:src/ts/gridPanel/gridPanel.ts": [
+453,
+458
+],
+"ag-grid:src/ts/headerRendering/headerRowComp.ts": [
+223
+]
+}
diff --git a/its/ruling/src/test/expected/jsts/console/typescript-S6836.json b/its/ruling/src/test/expected/jsts/console/typescript-S6836.json
new file mode 100644
index 00000000000..805acc31c24
--- /dev/null
+++ b/its/ruling/src/test/expected/jsts/console/typescript-S6836.json
@@ -0,0 +1,18 @@
+{
+"console:src/reducers/databrowser/data.ts": [
+31,
+44,
+105,
+113,
+114
+],
+"console:src/reducers/databrowser/ui.ts": [
+73
+],
+"console:src/reducers/gettingStarted.ts": [
+18
+],
+"console:src/views/models/DatabrowserView/DatabrowserView.tsx": [
+624
+]
+}
diff --git a/its/ruling/src/test/expected/jsts/desktop/typescript-S6836.json b/its/ruling/src/test/expected/jsts/desktop/typescript-S6836.json
new file mode 100644
index 00000000000..9e7678a8d3a
--- /dev/null
+++ b/its/ruling/src/test/expected/jsts/desktop/typescript-S6836.json
@@ -0,0 +1,76 @@
+{
+"desktop:app/src/lib/shells/win32.ts": [
+419,
+426,
+433,
+440,
+465,
+469
+],
+"desktop:app/src/lib/status.ts": [
+130
+],
+"desktop:app/src/lib/stores/app-store.ts": [
+6730
+],
+"desktop:app/src/lib/trampoline/trampoline-command-parser.ts": [
+73,
+83,
+84
+],
+"desktop:app/src/models/app-menu.ts": [
+220
+],
+"desktop:app/src/ui/about/about.tsx": [
+117
+],
+"desktop:app/src/ui/app.tsx": [
+1373,
+1412,
+1416,
+1449,
+1595,
+1680,
+1681,
+1927,
+1929,
+1974,
+1978,
+1979,
+1982,
+1986,
+1995
+],
+"desktop:app/src/ui/clone-repository/clone-repository.tsx": [
+300
+],
+"desktop:app/src/ui/diff/side-by-side-diff-row.tsx": [
+171
+],
+"desktop:app/src/ui/dispatcher/dispatcher.ts": [
+1818,
+1827,
+1828,
+1839,
+3704
+],
+"desktop:app/src/ui/drag-elements/commit-drag-element.tsx": [
+74,
+91,
+108
+],
+"desktop:app/src/ui/multi-commit-operation/base-multi-commit-operation.tsx": [
+157,
+216
+],
+"desktop:app/src/ui/sign-in/sign-in.tsx": [
+138
+],
+"desktop:app/src/ui/welcome/welcome.tsx": [
+141
+],
+"desktop:script/draft-release/version.ts": [
+48,
+64
+]
+}
diff --git a/its/ruling/src/test/expected/jsts/eigen/javascript-S6836.json b/its/ruling/src/test/expected/jsts/eigen/javascript-S6836.json
new file mode 100644
index 00000000000..6eb7665ee83
--- /dev/null
+++ b/its/ruling/src/test/expected/jsts/eigen/javascript-S6836.json
@@ -0,0 +1,8 @@
+{
+"eigen:scripts/strictness-migration.js": [
+44,
+47,
+79,
+81
+]
+}
diff --git a/its/ruling/src/test/expected/jsts/eigen/typescript-S6836.json b/its/ruling/src/test/expected/jsts/eigen/typescript-S6836.json
new file mode 100644
index 00000000000..83212b96ce7
--- /dev/null
+++ b/its/ruling/src/test/expected/jsts/eigen/typescript-S6836.json
@@ -0,0 +1,19 @@
+{
+"eigen:src/app/Scenes/Feature/Feature.tsx": [
+117,
+118,
+120,
+121
+],
+"eigen:src/app/Scenes/Onboarding/OnboardingCreateAccount/OnboardingCreateAccount.tsx": [
+103
+],
+"eigen:src/app/store/NativeModel.ts": [
+94
+],
+"eigen:src/app/utils/ArtworkInquiry/ArtworkInquiryStore.tsx": [
+42,
+43,
+44
+]
+}
diff --git a/its/ruling/src/test/expected/jsts/postgraphql/typescript-S6836.json b/its/ruling/src/test/expected/jsts/postgraphql/typescript-S6836.json
new file mode 100644
index 00000000000..ddfcbd02d6a
--- /dev/null
+++ b/its/ruling/src/test/expected/jsts/postgraphql/typescript-S6836.json
@@ -0,0 +1,6 @@
+{
+"postgraphql:src/postgres/inventory/conditionToSql.ts": [
+30,
+32
+]
+}
diff --git a/its/ruling/src/test/expected/jsts/reddit-mobile/javascript-S6836.json b/its/ruling/src/test/expected/jsts/reddit-mobile/javascript-S6836.json
new file mode 100644
index 00000000000..64c65fa393d
--- /dev/null
+++ b/its/ruling/src/test/expected/jsts/reddit-mobile/javascript-S6836.json
@@ -0,0 +1,5 @@
+{
+"reddit-mobile:index.js": [
+201
+]
+}
diff --git a/its/ruling/src/test/expected/jsts/redux/javascript-S6836.json b/its/ruling/src/test/expected/jsts/redux/javascript-S6836.json
new file mode 100644
index 00000000000..f013e43ca7b
--- /dev/null
+++ b/its/ruling/src/test/expected/jsts/redux/javascript-S6836.json
@@ -0,0 +1,14 @@
+{
+"redux:examples/real-world/reducers/paginate.js": [
+51
+],
+"redux:examples/shopping-cart/reducers/cart.js": [
+27
+],
+"redux:examples/shopping-cart/reducers/products.js": [
+27
+],
+"redux:examples/todomvc/reducers/todos.js": [
+43
+]
+}
diff --git a/its/ruling/src/test/expected/jsts/vuetify/typescript-S6836.json b/its/ruling/src/test/expected/jsts/vuetify/typescript-S6836.json
new file mode 100644
index 00000000000..df580a09772
--- /dev/null
+++ b/its/ruling/src/test/expected/jsts/vuetify/typescript-S6836.json
@@ -0,0 +1,8 @@
+{
+"vuetify:packages/api-generator/src/types.ts": [
+270
+],
+"vuetify:packages/vuetify/src/components/VCalendar/VCalendar.ts": [
+126
+]
+}
diff --git a/sonar-plugin/javascript-checks/src/main/java/org/sonar/javascript/checks/CheckList.java b/sonar-plugin/javascript-checks/src/main/java/org/sonar/javascript/checks/CheckList.java
index c0d7530cead..db31f1e386f 100644
--- a/sonar-plugin/javascript-checks/src/main/java/org/sonar/javascript/checks/CheckList.java
+++ b/sonar-plugin/javascript-checks/src/main/java/org/sonar/javascript/checks/CheckList.java
@@ -240,6 +240,7 @@ public static List<Class<? extends JavaScriptCheck>> getAllChecks() {
       NoArrayDeleteCheck.class,
       NoArrayIndexKeyCheck.class,
       NoBaseToStringCheck.class,
+      NoCaseDeclarationsCheck.class,
       NoChildrenPropCheck.class,
       NoClearTextProtocolsCheck.class,
       NoCodeAfterDoneCheck.class,
diff --git a/sonar-plugin/javascript-checks/src/main/java/org/sonar/javascript/checks/NoCaseDeclarationsCheck.java b/sonar-plugin/javascript-checks/src/main/java/org/sonar/javascript/checks/NoCaseDeclarationsCheck.java
new file mode 100644
index 00000000000..64e8b8ce0ef
--- /dev/null
+++ b/sonar-plugin/javascript-checks/src/main/java/org/sonar/javascript/checks/NoCaseDeclarationsCheck.java
@@ -0,0 +1,36 @@
+/**
+ * SonarQube JavaScript Plugin
+ * Copyright (C) 2011-2023 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.javascript.checks;
+
+import org.sonar.check.Rule;
+import org.sonar.plugins.javascript.api.EslintBasedCheck;
+import org.sonar.plugins.javascript.api.JavaScriptRule;
+import org.sonar.plugins.javascript.api.TypeScriptRule;
+
+@JavaScriptRule
+@TypeScriptRule
+@Rule(key = "S6836")
+public class NoCaseDeclarationsCheck implements EslintBasedCheck {
+
+  @Override
+  public String eslintKey() {
+    return "no-case-declarations";
+  }
+}
diff --git a/sonar-plugin/javascript-checks/src/main/resources/org/sonar/l10n/javascript/rules/javascript/S6836.html b/sonar-plugin/javascript-checks/src/main/resources/org/sonar/l10n/javascript/rules/javascript/S6836.html
new file mode 100644
index 00000000000..b14d7f0cbf4
--- /dev/null
+++ b/sonar-plugin/javascript-checks/src/main/resources/org/sonar/l10n/javascript/rules/javascript/S6836.html
@@ -0,0 +1,49 @@
+<h2>Why is this an issue?</h2>
+<p>The ECMAScript specification allows for creating block-level lexical declarations (<code>let</code>, <code>const</code>, <code>function</code>, and
+<code>class</code>) in any block statement or expression. However, when these declarations are made inside a <code>case</code> or <code>default</code>
+clause of a <code>switch</code> statement, they are not confined to the block of that <code>case</code> or <code>default</code> clause. Instead, they
+apply to the whole <code>switch</code> block but only get initialized when the cases are reached, which can lead to unexpected behavior.</p>
+<pre data-diff-id="1" data-diff-type="noncompliant">
+switch (foo) {
+    case 1:
+        let x = 1; // Noncompliant
+        break;
+    case 2:
+        const y = 2; // Noncompliant
+        break;
+    case 3:
+        function f() {} // Noncompliant
+        break;
+    case 4:
+        class C {} // Noncompliant
+        break;
+}
+</pre>
+<p>To fix this, you can create a nested block within each <code>case</code> or <code>default</code> clause, ensuring each declaration is properly
+scoped to its respective block.</p>
+<pre data-diff-id="1" data-diff-type="compliant">
+switch (foo) {
+    case 1: {
+        let x = 1;
+        break;
+    }
+    case 2: {
+        const y = 2;
+        break;
+    }
+    case 3: {
+        function f() {}
+        break;
+    }
+    case 4: {
+        class C {}
+        break;
+    }
+}
+</pre>
+<h2>Resources</h2>
+<h3>Documentation</h3>
+<ul>
+  <li> MDN web docs - <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/switch">switch</a> </li>
+</ul>
+
diff --git a/sonar-plugin/javascript-checks/src/main/resources/org/sonar/l10n/javascript/rules/javascript/S6836.json b/sonar-plugin/javascript-checks/src/main/resources/org/sonar/l10n/javascript/rules/javascript/S6836.json
new file mode 100644
index 00000000000..2015e6b2598
--- /dev/null
+++ b/sonar-plugin/javascript-checks/src/main/resources/org/sonar/l10n/javascript/rules/javascript/S6836.json
@@ -0,0 +1,25 @@
+{
+  "title": "\"case\" and \"default\" clauses should not contain lexical declarations",
+  "type": "CODE_SMELL",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [],
+  "defaultSeverity": "Major",
+  "ruleSpecification": "RSPEC-6836",
+  "sqKey": "S6836",
+  "scope": "All",
+  "quickfix": "unknown",
+  "code": {
+    "impacts": {
+      "MAINTAINABILITY": "MEDIUM"
+    },
+    "attribute": "CONVENTIONAL"
+  },
+  "compatibleLanguages": [
+    "JAVASCRIPT",
+    "TYPESCRIPT"
+  ]
+}
diff --git a/sonar-plugin/javascript-checks/src/main/resources/org/sonar/l10n/javascript/rules/javascript/Sonar_way_profile.json b/sonar-plugin/javascript-checks/src/main/resources/org/sonar/l10n/javascript/rules/javascript/Sonar_way_profile.json
index 91b7eb4c9f6..38d39b0a02b 100644
--- a/sonar-plugin/javascript-checks/src/main/resources/org/sonar/l10n/javascript/rules/javascript/Sonar_way_profile.json
+++ b/sonar-plugin/javascript-checks/src/main/resources/org/sonar/l10n/javascript/rules/javascript/Sonar_way_profile.json
@@ -301,6 +301,7 @@
     "S6823",
     "S6824",
     "S6825",
-    "S6827"
+    "S6827",
+    "S6836"
   ]
 }