diff --git a/packages/devextreme-angular/src/ui/accordion/index.ts b/packages/devextreme-angular/src/ui/accordion/index.ts
index ddb3115661b2..912f168b3fa0 100644
--- a/packages/devextreme-angular/src/ui/accordion/index.ts
+++ b/packages/devextreme-angular/src/ui/accordion/index.ts
@@ -288,10 +288,10 @@ export class DxAccordionComponent<TItem = any, TKey = any> extends DxComponent i
     
      */
     @Input()
-    get keyExpr(): Function | string {
+    get keyExpr(): (() => string) | string {
         return this._getOption('keyExpr');
     }
-    set keyExpr(value: Function | string) {
+    set keyExpr(value: (() => string) | string) {
         this._setOption('keyExpr', value);
     }
 
@@ -635,7 +635,7 @@ export class DxAccordionComponent<TItem = any, TKey = any> extends DxComponent i
      * This member supports the internal infrastructure and is not intended to be used directly from your code.
     
      */
-    @Output() keyExprChange: EventEmitter<Function | string>;
+    @Output() keyExprChange: EventEmitter<(() => string) | string>;
 
     /**
     
diff --git a/packages/devextreme-angular/src/ui/list/index.ts b/packages/devextreme-angular/src/ui/list/index.ts
index 42888b4f9690..2b6ccda4ce49 100644
--- a/packages/devextreme-angular/src/ui/list/index.ts
+++ b/packages/devextreme-angular/src/ui/list/index.ts
@@ -380,10 +380,10 @@ export class DxListComponent<TItem = any, TKey = any> extends DxComponent implem
     
      */
     @Input()
-    get keyExpr(): Function | string {
+    get keyExpr(): (() => string) | string {
         return this._getOption('keyExpr');
     }
-    set keyExpr(value: Function | string) {
+    set keyExpr(value: (() => string) | string) {
         this._setOption('keyExpr', value);
     }
 
@@ -1120,7 +1120,7 @@ export class DxListComponent<TItem = any, TKey = any> extends DxComponent implem
      * This member supports the internal infrastructure and is not intended to be used directly from your code.
     
      */
-    @Output() keyExprChange: EventEmitter<Function | string>;
+    @Output() keyExprChange: EventEmitter<(() => string) | string>;
 
     /**
     
diff --git a/packages/devextreme-angular/src/ui/tabs/index.ts b/packages/devextreme-angular/src/ui/tabs/index.ts
index 501b4011d135..4e0111770014 100644
--- a/packages/devextreme-angular/src/ui/tabs/index.ts
+++ b/packages/devextreme-angular/src/ui/tabs/index.ts
@@ -237,10 +237,10 @@ export class DxTabsComponent<TItem = any, TKey = any> extends DxComponent implem
     
      */
     @Input()
-    get keyExpr(): Function | string {
+    get keyExpr(): (() => string) | string {
         return this._getOption('keyExpr');
     }
-    set keyExpr(value: Function | string) {
+    set keyExpr(value: (() => string) | string) {
         this._setOption('keyExpr', value);
     }
 
@@ -621,7 +621,7 @@ export class DxTabsComponent<TItem = any, TKey = any> extends DxComponent implem
      * This member supports the internal infrastructure and is not intended to be used directly from your code.
     
      */
-    @Output() keyExprChange: EventEmitter<Function | string>;
+    @Output() keyExprChange: EventEmitter<(() => string) | string>;
 
     /**
     
diff --git a/packages/devextreme-vue/src/accordion.ts b/packages/devextreme-vue/src/accordion.ts
index 558c466fd0c1..547a1970e45e 100644
--- a/packages/devextreme-vue/src/accordion.ts
+++ b/packages/devextreme-vue/src/accordion.ts
@@ -88,7 +88,7 @@ const componentConfig = {
     items: Array as PropType<Array<any | dxAccordionItem | string>>,
     itemTemplate: {},
     itemTitleTemplate: {},
-    keyExpr: [Function, String] as PropType<((() => void)) | string>,
+    keyExpr: [Function, String] as PropType<((() => string)) | string>,
     multiple: Boolean,
     noDataText: String,
     onContentReady: Function as PropType<((e: ContentReadyEvent) => void)>,
diff --git a/packages/devextreme-vue/src/list.ts b/packages/devextreme-vue/src/list.ts
index 47113d5ea735..a747d3e13d8e 100644
--- a/packages/devextreme-vue/src/list.ts
+++ b/packages/devextreme-vue/src/list.ts
@@ -201,7 +201,7 @@ const componentConfig = {
     itemHoldTimeout: Number,
     items: Array as PropType<Array<any | dxListItem | string>>,
     itemTemplate: {},
-    keyExpr: [Function, String] as PropType<((() => void)) | string>,
+    keyExpr: [Function, String] as PropType<((() => string)) | string>,
     menuItems: Array as PropType<Array<Record<string, any>>>,
     menuMode: String as PropType<ListMenuMode>,
     nextButtonText: String,
diff --git a/packages/devextreme-vue/src/tabs.ts b/packages/devextreme-vue/src/tabs.ts
index 78bf15abb259..8d5e0ddbaa0c 100644
--- a/packages/devextreme-vue/src/tabs.ts
+++ b/packages/devextreme-vue/src/tabs.ts
@@ -91,7 +91,7 @@ const componentConfig = {
     itemHoldTimeout: Number,
     items: Array as PropType<Array<any | dxTabsItem | string>>,
     itemTemplate: {},
-    keyExpr: [Function, String] as PropType<((() => void)) | string>,
+    keyExpr: [Function, String] as PropType<((() => string)) | string>,
     noDataText: String,
     onContentReady: Function as PropType<((e: ContentReadyEvent) => void)>,
     onDisposing: Function as PropType<((e: DisposingEvent) => void)>,
diff --git a/packages/devextreme/js/ui/collection/ui.collection_widget.base.d.ts b/packages/devextreme/js/ui/collection/ui.collection_widget.base.d.ts
index d68c4b641fe5..e4007ad2fe65 100644
--- a/packages/devextreme/js/ui/collection/ui.collection_widget.base.d.ts
+++ b/packages/devextreme/js/ui/collection/ui.collection_widget.base.d.ts
@@ -80,7 +80,7 @@ export interface CollectionWidgetOptions<
      * @default null
      * @public
      */
-    keyExpr?: string | Function;
+    keyExpr?: string | (() => string);
     /**
      * @docid
      * @default "No data to display"
diff --git a/packages/devextreme/ts/dx.all.d.ts b/packages/devextreme/ts/dx.all.d.ts
index 51da85b9e775..d0f0859a95fb 100644
--- a/packages/devextreme/ts/dx.all.d.ts
+++ b/packages/devextreme/ts/dx.all.d.ts
@@ -8771,7 +8771,7 @@ declare module DevExpress.ui {
     /**
      * [descr:CollectionWidgetOptions.keyExpr]
      */
-    keyExpr?: string | Function;
+    keyExpr?: string | (() => string);
     /**
      * [descr:CollectionWidgetOptions.noDataText]
      */