diff --git a/compat/src/render.js b/compat/src/render.js
index 302d19589e..b643f18654 100644
--- a/compat/src/render.js
+++ b/compat/src/render.js
@@ -39,33 +39,6 @@ const onChangeInputType = type => /fil|che|rad/.test(type);
 // Some libraries like `react-virtualized` explicitly check for this.
 Component.prototype.isReactComponent = {};
 
-// `UNSAFE_*` lifecycle hooks
-// Preact only ever invokes the unprefixed methods.
-// Here we provide a base "fallback" implementation that calls any defined UNSAFE_ prefixed method.
-// - If a component defines its own `componentDidMount()` (including via defineProperty), use that.
-// - If a component defines `UNSAFE_componentDidMount()`, `componentDidMount` is the alias getter/setter.
-// - If anything assigns to an `UNSAFE_*` property, the assignment is forwarded to the unprefixed property.
-// See https://github.com/preactjs/preact/issues/1941
-[
-	'componentWillMount',
-	'componentWillReceiveProps',
-	'componentWillUpdate'
-].forEach(key => {
-	Object.defineProperty(Component.prototype, key, {
-		configurable: true,
-		get() {
-			return this['UNSAFE_' + key];
-		},
-		set(v) {
-			Object.defineProperty(this, key, {
-				configurable: true,
-				writable: true,
-				value: v
-			});
-		}
-	});
-});
-
 /**
  * Proxy render() since React returns a Component reference.
  * @param {import('./internal').VNode} vnode VNode tree to render
diff --git a/compat/test/browser/component.test.js b/compat/test/browser/component.test.js
index de78a1fd20..9aecf754bc 100644
--- a/compat/test/browser/component.test.js
+++ b/compat/test/browser/component.test.js
@@ -75,169 +75,4 @@ describe('components', () => {
 			children: 'second'
 		});
 	});
-
-	describe('UNSAFE_* lifecycle methods', () => {
-		it('should support UNSAFE_componentWillMount', () => {
-			let spy = sinon.spy();
-
-			class Foo extends React.Component {
-				// eslint-disable-next-line camelcase
-				UNSAFE_componentWillMount() {
-					spy();
-				}
-
-				render() {
-					return <h1>foo</h1>;
-				}
-			}
-
-			React.render(<Foo />, scratch);
-
-			expect(spy).to.be.calledOnce;
-		});
-
-		it('should support UNSAFE_componentWillMount #2', () => {
-			let spy = sinon.spy();
-
-			class Foo extends React.Component {
-				render() {
-					return <h1>foo</h1>;
-				}
-			}
-
-			Object.defineProperty(Foo.prototype, 'UNSAFE_componentWillMount', {
-				value: spy
-			});
-
-			React.render(<Foo />, scratch);
-			expect(spy).to.be.calledOnce;
-		});
-
-		it('should support UNSAFE_componentWillReceiveProps', () => {
-			let spy = sinon.spy();
-
-			class Foo extends React.Component {
-				// eslint-disable-next-line camelcase
-				UNSAFE_componentWillReceiveProps() {
-					spy();
-				}
-
-				render() {
-					return <h1>foo</h1>;
-				}
-			}
-
-			React.render(<Foo />, scratch);
-			// Trigger an update
-			React.render(<Foo />, scratch);
-			expect(spy).to.be.calledOnce;
-		});
-
-		it('should support UNSAFE_componentWillReceiveProps #2', () => {
-			let spy = sinon.spy();
-
-			class Foo extends React.Component {
-				render() {
-					return <h1>foo</h1>;
-				}
-			}
-
-			Object.defineProperty(Foo.prototype, 'UNSAFE_componentWillReceiveProps', {
-				value: spy
-			});
-
-			React.render(<Foo />, scratch);
-			// Trigger an update
-			React.render(<Foo />, scratch);
-			expect(spy).to.be.calledOnce;
-		});
-
-		it('should support UNSAFE_componentWillUpdate', () => {
-			let spy = sinon.spy();
-
-			class Foo extends React.Component {
-				// eslint-disable-next-line camelcase
-				UNSAFE_componentWillUpdate() {
-					spy();
-				}
-
-				render() {
-					return <h1>foo</h1>;
-				}
-			}
-
-			React.render(<Foo />, scratch);
-			// Trigger an update
-			React.render(<Foo />, scratch);
-			expect(spy).to.be.calledOnce;
-		});
-
-		it('should support UNSAFE_componentWillUpdate #2', () => {
-			let spy = sinon.spy();
-
-			class Foo extends React.Component {
-				render() {
-					return <h1>foo</h1>;
-				}
-			}
-
-			Object.defineProperty(Foo.prototype, 'UNSAFE_componentWillUpdate', {
-				value: spy
-			});
-
-			React.render(<Foo />, scratch);
-			// Trigger an update
-			React.render(<Foo />, scratch);
-			expect(spy).to.be.calledOnce;
-		});
-
-		it('should alias UNSAFE_* method to non-prefixed variant', () => {
-			let inst;
-			class Foo extends React.Component {
-				// eslint-disable-next-line camelcase
-				UNSAFE_componentWillMount() {}
-				// eslint-disable-next-line camelcase
-				UNSAFE_componentWillReceiveProps() {}
-				// eslint-disable-next-line camelcase
-				UNSAFE_componentWillUpdate() {}
-				render() {
-					inst = this;
-					return <div>foo</div>;
-				}
-			}
-
-			React.render(<Foo />, scratch);
-
-			expect(inst.UNSAFE_componentWillMount).to.equal(inst.componentWillMount);
-			expect(inst.UNSAFE_componentWillReceiveProps).to.equal(
-				inst.UNSAFE_componentWillReceiveProps
-			);
-			expect(inst.UNSAFE_componentWillUpdate).to.equal(
-				inst.UNSAFE_componentWillUpdate
-			);
-		});
-
-		it('should call UNSAFE_* methods through Suspense with wrapper component #2525', () => {
-			class Page extends React.Component {
-				UNSAFE_componentWillMount() {}
-				render() {
-					return <h1>Example</h1>;
-				}
-			}
-
-			const Wrapper = () => <Page />;
-
-			sinon.spy(Page.prototype, 'UNSAFE_componentWillMount');
-
-			React.render(
-				<React.Suspense fallback={<div>fallback</div>}>
-					<Wrapper />
-				</React.Suspense>,
-				scratch
-			);
-
-			expect(scratch.innerHTML).to.equal('<h1>Example</h1>');
-			expect(Page.prototype.UNSAFE_componentWillMount).to.have.been.called;
-		});
-	});
 });