diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 75be36474222f..2673da7dcc8bf 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -14720,7 +14720,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             cb(getLiteralTypeFromProperty(prop, include));
         }
         if (type.flags & TypeFlags.Any) {
-            cb(stringType);
+            forEachType(stringsOnly ? stringType : stringNumberSymbolType, cb);
         }
         else {
             for (const info of getIndexInfosOfType(type)) {
@@ -14759,7 +14759,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
 
         function addMemberForKeyType(keyType: Type) {
             const propNameType = nameType ? instantiateType(nameType, appendTypeMapping(type.mapper, typeParameter, keyType)) : keyType;
-            forEachType(propNameType, t => addMemberForKeyTypeWorker(keyType, t));
+            forEachType(keyType.flags & TypeFlags.Any ? stringNumberSymbolType : propNameType, t => addMemberForKeyTypeWorker(keyType, t));
         }
 
         function addMemberForKeyTypeWorker(keyType: Type, propNameType: Type) {
@@ -14794,10 +14794,8 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                     members.set(propName, prop);
                 }
             }
-            else if (isValidIndexKeyType(propNameType) || propNameType.flags & (TypeFlags.Any | TypeFlags.Enum)) {
-                const indexKeyType = propNameType.flags & (TypeFlags.Any | TypeFlags.String) ? stringType :
-                    propNameType.flags & (TypeFlags.Number | TypeFlags.Enum) ? numberType :
-                    propNameType;
+            else if (isValidIndexKeyType(propNameType) || propNameType.flags & TypeFlags.Enum) {
+                const indexKeyType = propNameType.flags & (TypeFlags.Number | TypeFlags.Enum) ? numberType : propNameType;
                 const propType = instantiateType(templateType, appendTypeMapping(type.mapper, typeParameter, keyType));
                 const modifiersIndexInfo = getApplicableIndexInfo(modifiersType, propNameType);
                 const isReadonly = !!(templateModifiers & MappedTypeModifiers.IncludeReadonly ||
diff --git a/tests/baselines/reference/mappedTypeWithAny.errors.txt b/tests/baselines/reference/mappedTypeWithAny.errors.txt
index f53402fd7fcb4..4652b49a4b741 100644
--- a/tests/baselines/reference/mappedTypeWithAny.errors.txt
+++ b/tests/baselines/reference/mappedTypeWithAny.errors.txt
@@ -77,4 +77,18 @@ mappedTypeWithAny.ts(53,5): error TS2322: Type 'string[]' is not assignable to t
     type Evolver<T extends Evolvable<any> = any> = {
       [key in keyof Partial<T>]: never;
     };
+    
+    // https://github.com/microsoft/TypeScript/issues/61203
+    type Obj61203 = { [k in keyof any]: number };
+    declare const obj61203: Obj61203;
+    declare const key61203: keyof Obj61203;
+    obj61203[key61203]; // ok
+    
+    
+    // https://github.com/microsoft/TypeScript/issues/61203#issuecomment-2703862148
+    type A<T> = { [k in keyof T]: 1 };
+    declare function iDontKnow<T>(a: T): [ A<T>, keyof T ];
+    const something: any = { a: 1, b: 2 };
+    const [ o, k ] = iDontKnow(something);
+    const v = o[k]; // ok
     
\ No newline at end of file
diff --git a/tests/baselines/reference/mappedTypeWithAny.js b/tests/baselines/reference/mappedTypeWithAny.js
index a01d8a6653f42..c97401846db45 100644
--- a/tests/baselines/reference/mappedTypeWithAny.js
+++ b/tests/baselines/reference/mappedTypeWithAny.js
@@ -63,6 +63,20 @@ type Evolvable<E extends Evolver> = {
 type Evolver<T extends Evolvable<any> = any> = {
   [key in keyof Partial<T>]: never;
 };
+
+// https://github.com/microsoft/TypeScript/issues/61203
+type Obj61203 = { [k in keyof any]: number };
+declare const obj61203: Obj61203;
+declare const key61203: keyof Obj61203;
+obj61203[key61203]; // ok
+
+
+// https://github.com/microsoft/TypeScript/issues/61203#issuecomment-2703862148
+type A<T> = { [k in keyof T]: 1 };
+declare function iDontKnow<T>(a: T): [ A<T>, keyof T ];
+const something: any = { a: 1, b: 2 };
+const [ o, k ] = iDontKnow(something);
+const v = o[k]; // ok
 
 
 //// [mappedTypeWithAny.js]
@@ -79,6 +93,10 @@ function bar(arrayish, objectish, indirectArrayish) {
 }
 var abc = stringifyArray(void 0);
 var def = stringifyPair(void 0);
+obj61203[key61203]; // ok
+var something = { a: 1, b: 2 };
+var _a = iDontKnow(something), o = _a[0], k = _a[1];
+var v = o[k]; // ok
 
 
 //// [mappedTypeWithAny.d.ts]
@@ -128,3 +146,15 @@ type Evolvable<E extends Evolver> = {
 type Evolver<T extends Evolvable<any> = any> = {
     [key in keyof Partial<T>]: never;
 };
+type Obj61203 = {
+    [k in keyof any]: number;
+};
+declare const obj61203: Obj61203;
+declare const key61203: keyof Obj61203;
+type A<T> = {
+    [k in keyof T]: 1;
+};
+declare function iDontKnow<T>(a: T): [A<T>, keyof T];
+declare const something: any;
+declare const o: A<any>, k: string | number | symbol;
+declare const v: 1;
diff --git a/tests/baselines/reference/mappedTypeWithAny.symbols b/tests/baselines/reference/mappedTypeWithAny.symbols
index b52536f518bc4..4b9d8696e34a4 100644
--- a/tests/baselines/reference/mappedTypeWithAny.symbols
+++ b/tests/baselines/reference/mappedTypeWithAny.symbols
@@ -177,3 +177,53 @@ type Evolver<T extends Evolvable<any> = any> = {
 
 };
 
+// https://github.com/microsoft/TypeScript/issues/61203
+type Obj61203 = { [k in keyof any]: number };
+>Obj61203 : Symbol(Obj61203, Decl(mappedTypeWithAny.ts, 61, 2))
+>k : Symbol(k, Decl(mappedTypeWithAny.ts, 64, 19))
+
+declare const obj61203: Obj61203;
+>obj61203 : Symbol(obj61203, Decl(mappedTypeWithAny.ts, 65, 13))
+>Obj61203 : Symbol(Obj61203, Decl(mappedTypeWithAny.ts, 61, 2))
+
+declare const key61203: keyof Obj61203;
+>key61203 : Symbol(key61203, Decl(mappedTypeWithAny.ts, 66, 13))
+>Obj61203 : Symbol(Obj61203, Decl(mappedTypeWithAny.ts, 61, 2))
+
+obj61203[key61203]; // ok
+>obj61203 : Symbol(obj61203, Decl(mappedTypeWithAny.ts, 65, 13))
+>key61203 : Symbol(key61203, Decl(mappedTypeWithAny.ts, 66, 13))
+
+
+// https://github.com/microsoft/TypeScript/issues/61203#issuecomment-2703862148
+type A<T> = { [k in keyof T]: 1 };
+>A : Symbol(A, Decl(mappedTypeWithAny.ts, 67, 19))
+>T : Symbol(T, Decl(mappedTypeWithAny.ts, 71, 7))
+>k : Symbol(k, Decl(mappedTypeWithAny.ts, 71, 15))
+>T : Symbol(T, Decl(mappedTypeWithAny.ts, 71, 7))
+
+declare function iDontKnow<T>(a: T): [ A<T>, keyof T ];
+>iDontKnow : Symbol(iDontKnow, Decl(mappedTypeWithAny.ts, 71, 34))
+>T : Symbol(T, Decl(mappedTypeWithAny.ts, 72, 27))
+>a : Symbol(a, Decl(mappedTypeWithAny.ts, 72, 30))
+>T : Symbol(T, Decl(mappedTypeWithAny.ts, 72, 27))
+>A : Symbol(A, Decl(mappedTypeWithAny.ts, 67, 19))
+>T : Symbol(T, Decl(mappedTypeWithAny.ts, 72, 27))
+>T : Symbol(T, Decl(mappedTypeWithAny.ts, 72, 27))
+
+const something: any = { a: 1, b: 2 };
+>something : Symbol(something, Decl(mappedTypeWithAny.ts, 73, 5))
+>a : Symbol(a, Decl(mappedTypeWithAny.ts, 73, 24))
+>b : Symbol(b, Decl(mappedTypeWithAny.ts, 73, 30))
+
+const [ o, k ] = iDontKnow(something);
+>o : Symbol(o, Decl(mappedTypeWithAny.ts, 74, 7))
+>k : Symbol(k, Decl(mappedTypeWithAny.ts, 74, 10))
+>iDontKnow : Symbol(iDontKnow, Decl(mappedTypeWithAny.ts, 71, 34))
+>something : Symbol(something, Decl(mappedTypeWithAny.ts, 73, 5))
+
+const v = o[k]; // ok
+>v : Symbol(v, Decl(mappedTypeWithAny.ts, 75, 5))
+>o : Symbol(o, Decl(mappedTypeWithAny.ts, 74, 7))
+>k : Symbol(k, Decl(mappedTypeWithAny.ts, 74, 10))
+
diff --git a/tests/baselines/reference/mappedTypeWithAny.types b/tests/baselines/reference/mappedTypeWithAny.types
index 587ff68bb42f3..f6cb60e0197eb 100644
--- a/tests/baselines/reference/mappedTypeWithAny.types
+++ b/tests/baselines/reference/mappedTypeWithAny.types
@@ -24,8 +24,8 @@ declare let x2: { [P in string]: Item };
 >   : ^^^^^^^^^^^^^^^^^^^^^^
 
 declare let x3: { [P in keyof any]: Item };
->x3 : { [x: string]: Item; }
->   : ^^^^^^^^^^^^^^^^^^^^^^
+>x3 : { [x: string]: Item; [x: number]: Item; [x: symbol]: Item; }
+>   : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 declare let x4: ItemMap<any>;
 >x4 : ItemMap<any>
@@ -197,3 +197,72 @@ type Evolver<T extends Evolvable<any> = any> = {
   [key in keyof Partial<T>]: never;
 };
 
+// https://github.com/microsoft/TypeScript/issues/61203
+type Obj61203 = { [k in keyof any]: number };
+>Obj61203 : Obj61203
+>         : ^^^^^^^^
+
+declare const obj61203: Obj61203;
+>obj61203 : Obj61203
+>         : ^^^^^^^^
+
+declare const key61203: keyof Obj61203;
+>key61203 : string | number | symbol
+>         : ^^^^^^^^^^^^^^^^^^^^^^^^
+
+obj61203[key61203]; // ok
+>obj61203[key61203] : number
+>                   : ^^^^^^
+>obj61203 : Obj61203
+>         : ^^^^^^^^
+>key61203 : string | number | symbol
+>         : ^^^^^^^^^^^^^^^^^^^^^^^^
+
+
+// https://github.com/microsoft/TypeScript/issues/61203#issuecomment-2703862148
+type A<T> = { [k in keyof T]: 1 };
+>A : A<T>
+>  : ^^^^
+
+declare function iDontKnow<T>(a: T): [ A<T>, keyof T ];
+>iDontKnow : <T>(a: T) => [A<T>, keyof T]
+>          : ^ ^^ ^^ ^^^^^               
+>a : T
+>  : ^
+
+const something: any = { a: 1, b: 2 };
+>something : any
+>          : ^^^
+>{ a: 1, b: 2 } : { a: number; b: number; }
+>               : ^^^^^^^^^^^^^^^^^^^^^^^^^
+>a : number
+>  : ^^^^^^
+>1 : 1
+>  : ^
+>b : number
+>  : ^^^^^^
+>2 : 2
+>  : ^
+
+const [ o, k ] = iDontKnow(something);
+>o : A<any>
+>  : ^^^^^^
+>k : string | number | symbol
+>  : ^^^^^^^^^^^^^^^^^^^^^^^^
+>iDontKnow(something) : [A<any>, string | number | symbol]
+>                     : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>iDontKnow : <T>(a: T) => [A<T>, keyof T]
+>          : ^ ^^ ^^ ^^^^^               
+>something : any
+>          : ^^^
+
+const v = o[k]; // ok
+>v : 1
+>  : ^
+>o[k] : 1
+>     : ^
+>o : A<any>
+>  : ^^^^^^
+>k : string | number | symbol
+>  : ^^^^^^^^^^^^^^^^^^^^^^^^
+
diff --git a/tests/cases/conformance/types/mapped/mappedTypeWithAny.ts b/tests/cases/conformance/types/mapped/mappedTypeWithAny.ts
index 89c28ddafc68f..50d4582939da7 100644
--- a/tests/cases/conformance/types/mapped/mappedTypeWithAny.ts
+++ b/tests/cases/conformance/types/mapped/mappedTypeWithAny.ts
@@ -63,3 +63,17 @@ type Evolvable<E extends Evolver> = {
 type Evolver<T extends Evolvable<any> = any> = {
   [key in keyof Partial<T>]: never;
 };
+
+// https://github.com/microsoft/TypeScript/issues/61203
+type Obj61203 = { [k in keyof any]: number };
+declare const obj61203: Obj61203;
+declare const key61203: keyof Obj61203;
+obj61203[key61203]; // ok
+
+
+// https://github.com/microsoft/TypeScript/issues/61203#issuecomment-2703862148
+type A<T> = { [k in keyof T]: 1 };
+declare function iDontKnow<T>(a: T): [ A<T>, keyof T ];
+const something: any = { a: 1, b: 2 };
+const [ o, k ] = iDontKnow(something);
+const v = o[k]; // ok