diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 0567712f11da3..06c06d1b749e2 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -6158,6 +6158,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 errorNode: firstIdentifier,
             };
         }
+        // Parameters are always in scope within their enclosing function; `typeof paramName` in a
+        // return type annotation is valid regardless of method visibility (public, protected, private).
+        if (symbol.declarations && every(symbol.declarations, isParameter)) {
+            return { accessibility: SymbolAccessibility.Accessible };
+        }
         // Verify if the symbol is accessible
         return hasVisibleDeclarations(symbol, shouldComputeAliasToMakeVisible) || {
             accessibility: SymbolAccessibility.NotAccessible,
diff --git a/src/compiler/transformers/declarations/diagnostics.ts b/src/compiler/transformers/declarations/diagnostics.ts
index 873f23cbf7987..1915820bd932f 100644
--- a/src/compiler/transformers/declarations/diagnostics.ts
+++ b/src/compiler/transformers/declarations/diagnostics.ts
@@ -353,7 +353,7 @@ export function createGetSymbolAccessibilityDiagnosticForNode(node: DeclarationD
         };
     }
 
-    function getReturnTypeVisibilityError(symbolAccessibilityResult: SymbolAccessibilityResult): SymbolAccessibilityDiagnostic {
+    function getReturnTypeVisibilityError(symbolAccessibilityResult: SymbolAccessibilityResult): SymbolAccessibilityDiagnostic | undefined {
         let diagnosticMessage: DiagnosticMessage;
         switch (node.kind) {
             case SyntaxKind.ConstructSignature:
diff --git a/tests/baselines/reference/protectedMethodTypeofParameter.d.symbols b/tests/baselines/reference/protectedMethodTypeofParameter.d.symbols
new file mode 100644
index 0000000000000..d739ff7dbb472
--- /dev/null
+++ b/tests/baselines/reference/protectedMethodTypeofParameter.d.symbols
@@ -0,0 +1,34 @@
+//// [tests/cases/compiler/protectedMethodTypeofParameter.d.ts] ////
+
+=== protectedMethodTypeofParameter.d.ts ===
+export interface Properties {
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.d.ts, 0, 0))
+
+    propertyA: number;
+>propertyA : Symbol(Properties.propertyA, Decl(protectedMethodTypeofParameter.d.ts, 0, 29))
+
+    propertyB: string;
+>propertyB : Symbol(Properties.propertyB, Decl(protectedMethodTypeofParameter.d.ts, 1, 22))
+}
+export declare class A {
+>A : Symbol(A, Decl(protectedMethodTypeofParameter.d.ts, 3, 1))
+
+    getPropertyValue_Ok(properties: Properties, propertyName: keyof Properties): Properties[typeof propertyName];
+>getPropertyValue_Ok : Symbol(A.getPropertyValue_Ok, Decl(protectedMethodTypeofParameter.d.ts, 4, 24))
+>properties : Symbol(properties, Decl(protectedMethodTypeofParameter.d.ts, 5, 24))
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.d.ts, 0, 0))
+>propertyName : Symbol(propertyName, Decl(protectedMethodTypeofParameter.d.ts, 5, 47))
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.d.ts, 0, 0))
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.d.ts, 0, 0))
+>propertyName : Symbol(propertyName, Decl(protectedMethodTypeofParameter.d.ts, 5, 47))
+
+    protected getPropertyValue_Error(properties: Properties, propertyName: keyof Properties): Properties[typeof propertyName];
+>getPropertyValue_Error : Symbol(A.getPropertyValue_Error, Decl(protectedMethodTypeofParameter.d.ts, 5, 113))
+>properties : Symbol(properties, Decl(protectedMethodTypeofParameter.d.ts, 6, 37))
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.d.ts, 0, 0))
+>propertyName : Symbol(propertyName, Decl(protectedMethodTypeofParameter.d.ts, 6, 60))
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.d.ts, 0, 0))
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.d.ts, 0, 0))
+>propertyName : Symbol(propertyName, Decl(protectedMethodTypeofParameter.d.ts, 6, 60))
+}
+
diff --git a/tests/baselines/reference/protectedMethodTypeofParameter.d.types b/tests/baselines/reference/protectedMethodTypeofParameter.d.types
new file mode 100644
index 0000000000000..006bae46cbece
--- /dev/null
+++ b/tests/baselines/reference/protectedMethodTypeofParameter.d.types
@@ -0,0 +1,37 @@
+//// [tests/cases/compiler/protectedMethodTypeofParameter.d.ts] ////
+
+=== protectedMethodTypeofParameter.d.ts ===
+export interface Properties {
+    propertyA: number;
+>propertyA : number
+>          : ^^^^^^
+
+    propertyB: string;
+>propertyB : string
+>          : ^^^^^^
+}
+export declare class A {
+>A : A
+>  : ^
+
+    getPropertyValue_Ok(properties: Properties, propertyName: keyof Properties): Properties[typeof propertyName];
+>getPropertyValue_Ok : (properties: Properties, propertyName: keyof Properties) => Properties[typeof propertyName]
+>                    : ^          ^^          ^^            ^^                ^^^^^                               
+>properties : Properties
+>           : ^^^^^^^^^^
+>propertyName : keyof Properties
+>             : ^^^^^^^^^^^^^^^^
+>propertyName : keyof Properties
+>             : ^^^^^^^^^^^^^^^^
+
+    protected getPropertyValue_Error(properties: Properties, propertyName: keyof Properties): Properties[typeof propertyName];
+>getPropertyValue_Error : (properties: Properties, propertyName: keyof Properties) => Properties[typeof propertyName]
+>                       : ^          ^^          ^^            ^^                ^^^^^                               
+>properties : Properties
+>           : ^^^^^^^^^^
+>propertyName : keyof Properties
+>             : ^^^^^^^^^^^^^^^^
+>propertyName : keyof Properties
+>             : ^^^^^^^^^^^^^^^^
+}
+
diff --git a/tests/baselines/reference/protectedMethodTypeofParameter.js b/tests/baselines/reference/protectedMethodTypeofParameter.js
new file mode 100644
index 0000000000000..713de599e49c2
--- /dev/null
+++ b/tests/baselines/reference/protectedMethodTypeofParameter.js
@@ -0,0 +1,45 @@
+//// [tests/cases/compiler/protectedMethodTypeofParameter.ts] ////
+
+//// [protectedMethodTypeofParameter.ts]
+export interface Properties {
+  propertyA: number;
+  propertyB: string;
+}
+
+export class A {
+  public getPropertyValue_Ok(
+    properties: Properties,
+    propertyName: keyof Properties,
+  ): Properties[typeof propertyName] {
+    return properties[propertyName];
+  }
+
+  protected getPropertyValue_Error(
+    properties: Properties,
+    propertyName: keyof Properties,
+  ): Properties[typeof propertyName] {
+    return properties[propertyName];
+  }
+}
+
+
+//// [protectedMethodTypeofParameter.js]
+export class A {
+    getPropertyValue_Ok(properties, propertyName) {
+        return properties[propertyName];
+    }
+    getPropertyValue_Error(properties, propertyName) {
+        return properties[propertyName];
+    }
+}
+
+
+//// [protectedMethodTypeofParameter.d.ts]
+export interface Properties {
+    propertyA: number;
+    propertyB: string;
+}
+export declare class A {
+    getPropertyValue_Ok(properties: Properties, propertyName: keyof Properties): Properties[typeof propertyName];
+    protected getPropertyValue_Error(properties: Properties, propertyName: keyof Properties): Properties[typeof propertyName];
+}
diff --git a/tests/baselines/reference/protectedMethodTypeofParameter.symbols b/tests/baselines/reference/protectedMethodTypeofParameter.symbols
new file mode 100644
index 0000000000000..391e783f1597f
--- /dev/null
+++ b/tests/baselines/reference/protectedMethodTypeofParameter.symbols
@@ -0,0 +1,57 @@
+//// [tests/cases/compiler/protectedMethodTypeofParameter.ts] ////
+
+=== protectedMethodTypeofParameter.ts ===
+export interface Properties {
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.ts, 0, 0))
+
+  propertyA: number;
+>propertyA : Symbol(Properties.propertyA, Decl(protectedMethodTypeofParameter.ts, 0, 29))
+
+  propertyB: string;
+>propertyB : Symbol(Properties.propertyB, Decl(protectedMethodTypeofParameter.ts, 1, 20))
+}
+
+export class A {
+>A : Symbol(A, Decl(protectedMethodTypeofParameter.ts, 3, 1))
+
+  public getPropertyValue_Ok(
+>getPropertyValue_Ok : Symbol(A.getPropertyValue_Ok, Decl(protectedMethodTypeofParameter.ts, 5, 16))
+
+    properties: Properties,
+>properties : Symbol(properties, Decl(protectedMethodTypeofParameter.ts, 6, 29))
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.ts, 0, 0))
+
+    propertyName: keyof Properties,
+>propertyName : Symbol(propertyName, Decl(protectedMethodTypeofParameter.ts, 7, 27))
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.ts, 0, 0))
+
+  ): Properties[typeof propertyName] {
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.ts, 0, 0))
+>propertyName : Symbol(propertyName, Decl(protectedMethodTypeofParameter.ts, 7, 27))
+
+    return properties[propertyName];
+>properties : Symbol(properties, Decl(protectedMethodTypeofParameter.ts, 6, 29))
+>propertyName : Symbol(propertyName, Decl(protectedMethodTypeofParameter.ts, 7, 27))
+  }
+
+  protected getPropertyValue_Error(
+>getPropertyValue_Error : Symbol(A.getPropertyValue_Error, Decl(protectedMethodTypeofParameter.ts, 11, 3))
+
+    properties: Properties,
+>properties : Symbol(properties, Decl(protectedMethodTypeofParameter.ts, 13, 35))
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.ts, 0, 0))
+
+    propertyName: keyof Properties,
+>propertyName : Symbol(propertyName, Decl(protectedMethodTypeofParameter.ts, 14, 27))
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.ts, 0, 0))
+
+  ): Properties[typeof propertyName] {
+>Properties : Symbol(Properties, Decl(protectedMethodTypeofParameter.ts, 0, 0))
+>propertyName : Symbol(propertyName, Decl(protectedMethodTypeofParameter.ts, 14, 27))
+
+    return properties[propertyName];
+>properties : Symbol(properties, Decl(protectedMethodTypeofParameter.ts, 13, 35))
+>propertyName : Symbol(propertyName, Decl(protectedMethodTypeofParameter.ts, 14, 27))
+  }
+}
+
diff --git a/tests/baselines/reference/protectedMethodTypeofParameter.types b/tests/baselines/reference/protectedMethodTypeofParameter.types
new file mode 100644
index 0000000000000..563ef66655f79
--- /dev/null
+++ b/tests/baselines/reference/protectedMethodTypeofParameter.types
@@ -0,0 +1,68 @@
+//// [tests/cases/compiler/protectedMethodTypeofParameter.ts] ////
+
+=== protectedMethodTypeofParameter.ts ===
+export interface Properties {
+  propertyA: number;
+>propertyA : number
+>          : ^^^^^^
+
+  propertyB: string;
+>propertyB : string
+>          : ^^^^^^
+}
+
+export class A {
+>A : A
+>  : ^
+
+  public getPropertyValue_Ok(
+>getPropertyValue_Ok : (properties: Properties, propertyName: keyof Properties) => Properties[typeof propertyName]
+>                    : ^          ^^          ^^            ^^                ^^^^^                               
+
+    properties: Properties,
+>properties : Properties
+>           : ^^^^^^^^^^
+
+    propertyName: keyof Properties,
+>propertyName : keyof Properties
+>             : ^^^^^^^^^^^^^^^^
+
+  ): Properties[typeof propertyName] {
+>propertyName : keyof Properties
+>             : ^^^^^^^^^^^^^^^^
+
+    return properties[propertyName];
+>properties[propertyName] : string | number
+>                         : ^^^^^^^^^^^^^^^
+>properties : Properties
+>           : ^^^^^^^^^^
+>propertyName : keyof Properties
+>             : ^^^^^^^^^^^^^^^^
+  }
+
+  protected getPropertyValue_Error(
+>getPropertyValue_Error : (properties: Properties, propertyName: keyof Properties) => Properties[typeof propertyName]
+>                       : ^          ^^          ^^            ^^                ^^^^^                               
+
+    properties: Properties,
+>properties : Properties
+>           : ^^^^^^^^^^
+
+    propertyName: keyof Properties,
+>propertyName : keyof Properties
+>             : ^^^^^^^^^^^^^^^^
+
+  ): Properties[typeof propertyName] {
+>propertyName : keyof Properties
+>             : ^^^^^^^^^^^^^^^^
+
+    return properties[propertyName];
+>properties[propertyName] : string | number
+>                         : ^^^^^^^^^^^^^^^
+>properties : Properties
+>           : ^^^^^^^^^^
+>propertyName : keyof Properties
+>             : ^^^^^^^^^^^^^^^^
+  }
+}
+
diff --git a/tests/cases/compiler/protectedMethodTypeofParameter.d.ts b/tests/cases/compiler/protectedMethodTypeofParameter.d.ts
new file mode 100644
index 0000000000000..8215fb0ad5865
--- /dev/null
+++ b/tests/cases/compiler/protectedMethodTypeofParameter.d.ts
@@ -0,0 +1,8 @@
+export interface Properties {
+    propertyA: number;
+    propertyB: string;
+}
+export declare class A {
+    getPropertyValue_Ok(properties: Properties, propertyName: keyof Properties): Properties[typeof propertyName];
+    protected getPropertyValue_Error(properties: Properties, propertyName: keyof Properties): Properties[typeof propertyName];
+}
diff --git a/tests/cases/compiler/protectedMethodTypeofParameter.ts b/tests/cases/compiler/protectedMethodTypeofParameter.ts
new file mode 100644
index 0000000000000..463494ff9494e
--- /dev/null
+++ b/tests/cases/compiler/protectedMethodTypeofParameter.ts
@@ -0,0 +1,22 @@
+// @declaration: true
+
+export interface Properties {
+  propertyA: number;
+  propertyB: string;
+}
+
+export class A {
+  public getPropertyValue_Ok(
+    properties: Properties,
+    propertyName: keyof Properties,
+  ): Properties[typeof propertyName] {
+    return properties[propertyName];
+  }
+
+  protected getPropertyValue_Error(
+    properties: Properties,
+    propertyName: keyof Properties,
+  ): Properties[typeof propertyName] {
+    return properties[propertyName];
+  }
+}