diff --git a/packages/base/src/Theming.ts b/packages/base/src/Theming.ts
index ffe80a2ab06c..7686b474d0a5 100644
--- a/packages/base/src/Theming.ts
+++ b/packages/base/src/Theming.ts
@@ -1,4 +1,9 @@
-import { addCustomCSS } from "./theming/CustomStyle.js";
+import { addCustomCSS, removeCustomCSS } from "./theming/CustomStyle.js";
 import { attachThemeLoaded, detachThemeLoaded } from "./theming/ThemeLoaded.js";
 
-export { addCustomCSS, attachThemeLoaded, detachThemeLoaded };
+export {
+	addCustomCSS,
+	removeCustomCSS,
+	attachThemeLoaded,
+	detachThemeLoaded,
+};
diff --git a/packages/base/src/index.ts b/packages/base/src/index.ts
index a73b95fd0f12..080721b274c4 100644
--- a/packages/base/src/index.ts
+++ b/packages/base/src/index.ts
@@ -101,7 +101,12 @@ import {
 } from "./Render.js";
 
 // Theming.ts
-import { addCustomCSS, attachThemeLoaded, detachThemeLoaded } from "./Theming.js";
+import {
+	addCustomCSS,
+	removeCustomCSS,
+	attachThemeLoaded,
+	detachThemeLoaded,
+} from "./Theming.js";
 
 // UI5Element.ts
 import UI5Element from "./UI5Element.js";
@@ -208,6 +213,7 @@ export {
 
 	// Theming.ts
 	addCustomCSS,
+	removeCustomCSS,
 	attachThemeLoaded,
 	detachThemeLoaded,
 
diff --git a/packages/base/src/theming/CustomStyle.ts b/packages/base/src/theming/CustomStyle.ts
index 1f12944b5be7..eb480e760dbb 100644
--- a/packages/base/src/theming/CustomStyle.ts
+++ b/packages/base/src/theming/CustomStyle.ts
@@ -3,10 +3,17 @@ import getSharedResource from "../getSharedResource.js";
 import EventProvider from "../EventProvider.js";
 
 type CustomCSSChangeCallback = (tag: string) => void;
+type CustomCSSEntry = { id: string, css: string };
 
 const getEventProvider = () => getSharedResource("CustomStyle.eventProvider", new EventProvider<string, void>());
 const CUSTOM_CSS_CHANGE = "CustomCSSChange";
 
+let currentId = 0;
+const nextId = () => {
+	currentId++;
+	return `custom-css-${currentId}`;
+};
+
 const attachCustomCSSChange = (listener: CustomCSSChangeCallback) => {
 	getEventProvider().attachEvent(CUSTOM_CSS_CHANGE, listener);
 };
@@ -19,7 +26,7 @@ const fireCustomCSSChange = (tag: string) => {
 	return getEventProvider().fireEvent(CUSTOM_CSS_CHANGE, tag);
 };
 
-const getCustomCSSFor = () => getSharedResource<Record<string, Array<string>>>("CustomStyle.customCSSFor", {});
+const getCustomCSSFor = () => getSharedResource<Record<string, Array<CustomCSSEntry>>>("CustomStyle.customCSSFor", {});
 
 // Listen to the eventProvider, in case other copies of this CustomStyle module fire this
 // event, and this copy would therefore need to reRender the ui5 webcomponents; but
@@ -31,13 +38,7 @@ attachCustomCSSChange((tag: string) => {
 	}
 });
 
-const addCustomCSS = (tag: string, css: string) => {
-	const customCSSFor = getCustomCSSFor();
-	if (!customCSSFor[tag]) {
-		customCSSFor[tag] = [];
-	}
-	customCSSFor[tag].push(css);
-
+const fireChangeAndRerender = (tag: string) => {
 	skipRerender = true;
 	try {
 		// The event is fired and the attached event listeners are all called synchronously
@@ -51,13 +52,43 @@ const addCustomCSS = (tag: string, css: string) => {
 	return reRenderAllUI5Elements({ tag });
 };
 
+const addCustomCSS = (tag: string, css: string): string => {
+	const customCSSFor = getCustomCSSFor();
+	if (!customCSSFor[tag]) {
+		customCSSFor[tag] = [];
+	}
+
+	const id = nextId();
+	customCSSFor[tag].push({ id, css });
+	fireChangeAndRerender(tag);
+
+	return id;
+};
+
+const removeCustomCSS = (tag: string, id: string) => {
+	const customCSSFor = getCustomCSSFor();
+	const entries = customCSSFor[tag];
+	if (!entries) {
+		return;
+	}
+
+	const index = entries.findIndex(entry => entry.id === id);
+	if (index === -1) {
+		return;
+	}
+
+	entries.splice(index, 1);
+	fireChangeAndRerender(tag);
+};
+
 const getCustomCSS = (tag: string) => {
 	const customCSSFor = getCustomCSSFor();
-	return customCSSFor[tag] ? customCSSFor[tag].join("") : "";
+	return customCSSFor[tag] ? customCSSFor[tag].map(entry => entry.css).join("") : "";
 };
 
 export {
 	addCustomCSS,
+	removeCustomCSS,
 	getCustomCSS,
 	attachCustomCSSChange,
 	detachCustomCSSChange,
diff --git a/packages/main/cypress/specs/CustomCSS.cy.tsx b/packages/main/cypress/specs/CustomCSS.cy.tsx
new file mode 100644
index 000000000000..ff2d221ec084
--- /dev/null
+++ b/packages/main/cypress/specs/CustomCSS.cy.tsx
@@ -0,0 +1,145 @@
+import { addCustomCSS, removeCustomCSS } from "@ui5/webcomponents-base/dist/Theming.js";
+import Select from "../../src/Select.js";
+import Option from "../../src/Option.js";
+
+describe("CustomCSS", () => {
+	it("addCustomCSS applies custom styles", () => {
+		cy.mount(
+			<Select id="sel">
+				<Option>Option 1</Option>
+			</Select>
+		);
+
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.then($el => {
+				addCustomCSS("ui5-select", ".ui5-select-root { background-color: rgb(255, 0, 0) !important; }");
+			});
+
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.should("have.css", "background-color", "rgb(255, 0, 0)");
+	});
+
+	it("addCustomCSS returns a string id", () => {
+		const id = addCustomCSS("ui5-select", ":host { /* noop */ }");
+
+		expect(id).to.be.a("string");
+		expect(id).to.include("custom-css-");
+	});
+
+	it("removeCustomCSS removes the applied custom styles", () => {
+		cy.mount(
+			<Select id="sel">
+				<Option>Option 1</Option>
+			</Select>
+		);
+
+		let cssId: string;
+
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.then(() => {
+				cssId = addCustomCSS("ui5-select", ".ui5-select-root { outline: 5px solid rgb(0, 128, 0); }");
+			});
+
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.should("have.css", "outline-color", "rgb(0, 128, 0)")
+			.then(() => {
+				removeCustomCSS("ui5-select", cssId);
+			});
+
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.should("not.have.css", "outline-color", "rgb(0, 128, 0)");
+	});
+
+	it("removeCustomCSS with invalid id does nothing", () => {
+		cy.mount(
+			<Select id="sel">
+				<Option>Option 1</Option>
+			</Select>
+		);
+
+		let cssId: string;
+
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.then(() => {
+				cssId = addCustomCSS("ui5-select", ".ui5-select-root { outline: 5px solid rgb(0, 0, 255); }");
+			});
+
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.should("have.css", "outline-color", "rgb(0, 0, 255)")
+			.then(() => {
+				removeCustomCSS("ui5-select", "non-existent-id");
+			});
+
+		// Style should still be applied
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.should("have.css", "outline-color", "rgb(0, 0, 255)")
+			.then(() => {
+				removeCustomCSS("ui5-select", cssId);
+			});
+	});
+
+	it("removeCustomCSS with non-existent tag does nothing", () => {
+		// Should not throw
+		removeCustomCSS("ui5-nonexistent", "some-id");
+	});
+
+	it("multiple addCustomCSS calls can be individually removed", () => {
+		cy.mount(
+			<Select id="sel">
+				<Option>Option 1</Option>
+			</Select>
+		);
+
+		let id1: string;
+		let id2: string;
+
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.then(() => {
+				id1 = addCustomCSS("ui5-select", ".ui5-select-root { outline: 3px solid rgb(255, 0, 0); }");
+				id2 = addCustomCSS("ui5-select", ".ui5-select-root { border: 3px solid rgb(0, 0, 255); }");
+			});
+
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.should("have.css", "outline-color", "rgb(255, 0, 0)")
+			.should("have.css", "border-color", "rgb(0, 0, 255)")
+			.then(() => {
+				removeCustomCSS("ui5-select", id1);
+			});
+
+		// First style removed, second still present
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.should("not.have.css", "outline-color", "rgb(255, 0, 0)")
+			.should("have.css", "border-color", "rgb(0, 0, 255)")
+			.then(() => {
+				removeCustomCSS("ui5-select", id2);
+			});
+
+		// Both removed
+		cy.get("[ui5-select]")
+			.shadow()
+			.find(".ui5-select-root")
+			.should("not.have.css", "border-color", "rgb(0, 0, 255)");
+	});
+});
diff --git a/packages/main/src/bundle.common.bootstrap.ts b/packages/main/src/bundle.common.bootstrap.ts
index fd20788fffac..3f5e86d1f295 100644
--- a/packages/main/src/bundle.common.bootstrap.ts
+++ b/packages/main/src/bundle.common.bootstrap.ts
@@ -20,7 +20,12 @@ import "@ui5/webcomponents-icons-business-suite/dist/Assets.js";
 import "@ui5/webcomponents-icons-business-suite/dist/AllIcons.js";
 
 import "@ui5/webcomponents-base/dist/features/F6Navigation.js";
-import { addCustomCSS, attachThemeLoaded, detachThemeLoaded } from "@ui5/webcomponents-base/dist/Theming.js";
+import {
+	addCustomCSS,
+	removeCustomCSS,
+	attachThemeLoaded,
+	detachThemeLoaded,
+} from "@ui5/webcomponents-base/dist/Theming.js";
 // import "./customI18n.js";
 
 // Calendars
@@ -119,6 +124,7 @@ const testAssets = {
 	detachLanguageChange,
 	ResizeHandler,
 	addCustomCSS,
+	removeCustomCSS,
 	attachThemeLoaded,
 	detachThemeLoaded,
 	getIconNames,
diff --git a/packages/main/test/pages/CustomCSS.html b/packages/main/test/pages/CustomCSS.html
index 28e071f869ac..863a6451b2ab 100644
--- a/packages/main/test/pages/CustomCSS.html
+++ b/packages/main/test/pages/CustomCSS.html
@@ -38,15 +38,33 @@
 	<br />
 	<br />
 
+	<ui5-button id="btn-remove">Remove custom css and rerender</ui5-button>
+
+	<br />
+	<br />
+
 	<script>
+		const customCSSIds = [];
+
 		const applyCustomCSSAndRerender = function() {
-			window["sap-ui-webcomponents-bundle"].addCustomCSS("ui5-select", ".ui5-select-root { background-color: red; } ");
+			const id = window["sap-ui-webcomponents-bundle"].addCustomCSS("ui5-select", ".ui5-select-root { background-color: red; } ");
+			customCSSIds.push(id);
+		};
+
+		const removeCustomCSSAndRerender = function() {
+			while (customCSSIds.length) {
+				window["sap-ui-webcomponents-bundle"].removeCustomCSS("ui5-select", customCSSIds.pop());
+			}
 		};
 
 		document
 			.getElementById("btn")
 			.addEventListener("click", applyCustomCSSAndRerender);
 
+		document
+			.getElementById("btn-remove")
+			.addEventListener("click", removeCustomCSSAndRerender);
+
 	</script>
 
 </body>