diff --git a/packages/base/src/util/isValidPropertyName.js b/packages/base/src/util/isValidPropertyName.js
index 76781ffa720c..10f22b3a3e86 100644
--- a/packages/base/src/util/isValidPropertyName.js
+++ b/packages/base/src/util/isValidPropertyName.js
@@ -1,6 +1,10 @@
 // Note: disabled is present in IE so we explicitly allow it here.
 // Others, such as ariaLabel, we explicitly override, so valid too
-const whitelist = ["disabled", "ariaLabel"];
+const whitelist = [
+	"disabled",
+	"ariaLabel",
+	"ariaExpanded",
+];
 
 /**
  * Checks whether a property name is valid (does not collide with existing DOM API properties)
diff --git a/packages/main/src/Button.hbs b/packages/main/src/Button.hbs
index ba3e2ed84654..ece21c109667 100644
--- a/packages/main/src/Button.hbs
+++ b/packages/main/src/Button.hbs
@@ -1,42 +1,42 @@
 <button
-		type="button"
-		class="ui5-button-root"
-		?disabled="{{disabled}}"
-		data-sap-focus-ref
-		{{> ariaPressed}}
-		dir="{{effectiveDir}}"
-		@focusout={{_onfocusout}}
-		@focusin={{_onfocusin}}
-		@click={{_onclick}}
-		@mousedown={{_onmousedown}}
-		@mouseup={{_onmouseup}}
-		@keydown={{_onkeydown}}
-		@keyup={{_onkeyup}}
-		tabindex={{tabIndexValue}}
-		aria-expanded="{{accInfo.ariaExpanded}}"
-		aria-controls="{{accInfo.ariaControls}}"
-		aria-haspopup="{{accInfo.ariaHaspopup}}"
-		aria-label="{{ariaLabelText}}"
-		title="{{accInfo.title}}"
-		part="button"
-	>
-		{{#if icon}}
-			<ui5-icon
-				class="ui5-button-icon"
-				name="{{icon}}"
-				show-tooltip={{iconOnly}}
-			></ui5-icon>
-		{{/if}}
+	type="button"
+	class="ui5-button-root"
+	?disabled="{{disabled}}"
+	data-sap-focus-ref
+	{{> ariaPressed}}
+	dir="{{effectiveDir}}"
+	@focusout={{_onfocusout}}
+	@focusin={{_onfocusin}}
+	@click={{_onclick}}
+	@mousedown={{_onmousedown}}
+	@mouseup={{_onmouseup}}
+	@keydown={{_onkeydown}}
+	@keyup={{_onkeyup}}
+	tabindex={{tabIndexValue}}
+	aria-expanded="{{accInfo.ariaExpanded}}"
+	aria-controls="{{accInfo.ariaControls}}"
+	aria-haspopup="{{accInfo.ariaHaspopup}}"
+	aria-label="{{ariaLabelText}}"
+	title="{{accInfo.title}}"
+	part="button"
+>
+	{{#if icon}}
+		<ui5-icon
+			class="ui5-button-icon"
+			name="{{icon}}"
+			show-tooltip={{iconOnly}}
+		></ui5-icon>
+	{{/if}}
 
-		<span id="{{_id}}-content" class="ui5-button-text">
-			<bdi>
-				<slot></slot>
-			</bdi>
-		</span>
+	<span id="{{_id}}-content" class="ui5-button-text">
+		<bdi>
+			<slot></slot>
+		</bdi>
+	</span>
 
-		{{#if hasButtonType}}
-			<span class="ui5-hidden-text">{{buttonTypeText}}</span>
-		{{/if}}
+	{{#if hasButtonType}}
+		<span class="ui5-hidden-text">{{buttonTypeText}}</span>
+	{{/if}}
 </button>
 
 {{#*inline "ariaPressed"}}{{/inline}}
diff --git a/packages/main/src/Button.js b/packages/main/src/Button.js
index b01522d1cd2d..039b66868ea3 100644
--- a/packages/main/src/Button.js
+++ b/packages/main/src/Button.js
@@ -153,6 +153,16 @@ const metadata = {
 			defaultValue: "",
 		},
 
+		/**
+		 * @type {String}
+		 * @defaultvalue ""
+		 * @public
+		 * @since 1.0.0-rc.8
+		 */
+		ariaExpanded: {
+			type: String,
+		},
+
 		/**
 		 * Indicates if the element if focusable
 		 * @private
@@ -340,7 +350,7 @@ class Button extends UI5Element {
 
 	get accInfo() {
 		return {
-			"ariaExpanded": this._buttonAccInfo && this._buttonAccInfo.ariaExpanded,
+			"ariaExpanded": this.ariaExpanded || (this._buttonAccInfo && this._buttonAccInfo.ariaExpanded),
 			"ariaControls": this._buttonAccInfo && this._buttonAccInfo.ariaControls,
 			"ariaHaspopup": this._buttonAccInfo && this._buttonAccInfo.ariaHaspopup,
 			"title": this._buttonAccInfo && this._buttonAccInfo.title,
diff --git a/packages/main/test/pages/Button.html b/packages/main/test/pages/Button.html
index 287c33c16a14..553fed99f651 100644
--- a/packages/main/test/pages/Button.html
+++ b/packages/main/test/pages/Button.html
@@ -41,7 +41,7 @@
 	<ui5-icon name="invalid_name"></ui5-icon>
 	<ui5-button design="Emphasized" icon="invalid_name">Press</ui5-button>
 
-	<ui5-button id="button1" design="Emphasized">Action Bar Button</ui5-button>
+	<ui5-button id="button1" design="Emphasized" aria-expanded="true">Action Bar Button</ui5-button>
 	<ui5-button style="height: auto">Primary <br> button</ui5-button>
 	<ui5-button style="height: auto" design="Transparent">Secondary <span style="color:red;">button</span></ui5-button>
 	<ui5-button disabled id="button-disabled">Inactive</ui5-button>
diff --git a/packages/main/test/specs/Button.spec.js b/packages/main/test/specs/Button.spec.js
index 255c61e63b0e..ac12cf7d3738 100644
--- a/packages/main/test/specs/Button.spec.js
+++ b/packages/main/test/specs/Button.spec.js
@@ -16,7 +16,7 @@ describe("Button general interaction", () => {
 
 		button.setAttribute("icon", "add");
 		assert.strictEqual(button.shadow$$("ui5-icon").length, 1, "icon is present");
-		
+
 		button.setAttribute("icon", "");
 		assert.strictEqual(button.shadow$$("ui5-icon").length, 0, "icon is not present");
 	});
@@ -78,4 +78,19 @@ describe("Button general interaction", () => {
 
 		assert.strictEqual(field.getProperty("value"), "6", "click should be called 6 times");
 	});
+
+	it("setting aria-expanded on the host is reflected on the button tag", () => {
+		const button = browser.$("#button1");
+		const innerButton = button.shadow$("button");
+
+		assert.strictEqual(innerButton.getAttribute("aria-expanded"), "true", "Attribute is reflected");
+
+		button.setAttribute("aria-expanded", "false");
+
+		assert.strictEqual(innerButton.getAttribute("aria-expanded"), "false", "Attribute is reflected");
+
+		button.removeAttribute("aria-expanded");
+
+		assert.strictEqual(innerButton.getAttribute("aria-expanded"), null, "Attribute is reflected");
+	})
 });