diff --git a/packages/block-directory/src/store/actions.js b/packages/block-directory/src/store/actions.js
index ec73abe2ffbdce..9f1e96d5db26ba 100644
--- a/packages/block-directory/src/store/actions.js
+++ b/packages/block-directory/src/store/actions.js
@@ -51,9 +51,6 @@ export function* installBlockType( block ) {
 	let success = false;
 	yield clearErrorNotice( id );
 	try {
-		if ( ! Array.isArray( assets ) || ! assets.length ) {
-			throw new Error( __( 'Block has no assets.' ) );
-		}
 		yield setIsInstalling( block.id, true );
 
 		// If we have a wp:plugin link, the plugin is installed but inactive.
diff --git a/packages/block-directory/src/store/controls.js b/packages/block-directory/src/store/controls.js
index f3f58536fa641d..a5ee96d8e6c9d4 100644
--- a/packages/block-directory/src/store/controls.js
+++ b/packages/block-directory/src/store/controls.js
@@ -1,50 +1,49 @@
 /**
  * WordPress dependencies
  */
-import { getPath } from '@wordpress/url';
+import apiFetch from '@wordpress/api-fetch';
 
 /**
- * Loads a JavaScript file.
+ * Load an asset for a block.
  *
- * @param {string} asset The url for this file.
+ * This function returns a Promise that will resolve once the asset is loaded,
+ * or in the case of Stylesheets and Inline Javascript, will resolve immediately.
+ *
+ * @param {HTMLElement} el A HTML Element asset to inject.
  *
  * @return {Promise} Promise which will resolve when the asset is loaded.
  */
-export const loadScript = ( asset ) => {
-	if ( ! asset || ! /\.js$/.test( getPath( asset ) ) ) {
-		return Promise.reject( new Error( 'No script found.' ) );
-	}
+export const loadAsset = ( el ) => {
 	return new Promise( ( resolve, reject ) => {
-		const existing = document.querySelector( `script[src="${ asset }"]` );
-		if ( existing ) {
-			existing.parentNode.removeChild( existing );
+		/*
+		 * Reconstruct the passed element, this is required as inserting the Node directly
+		 * won't always fire the required onload events, even if the asset wasn't already loaded.
+		 */
+		const newNode = document.createElement( el.nodeName );
+
+		[ 'id', 'rel', 'src', 'href', 'type' ].forEach( ( attr ) => {
+			if ( el[ attr ] ) {
+				newNode[ attr ] = el[ attr ];
+			}
+		} );
+
+		// Append inline <script> contents.
+		if ( el.innerHTML ) {
+			newNode.appendChild( document.createTextNode( el.innerHTML ) );
 		}
-		const script = document.createElement( 'script' );
-		script.src = asset;
-		script.onload = () => resolve( true );
-		script.onerror = () => reject( new Error( 'Error loading script.' ) );
-		document.body.appendChild( script );
-	} );
-};
 
-/**
- * Loads a CSS file.
- *
- * @param {string} asset The url for this file.
- *
- * @return {Promise} Promise which will resolve when the asset is added.
- */
-export const loadStyle = ( asset ) => {
-	if ( ! asset || ! /\.css$/.test( getPath( asset ) ) ) {
-		return Promise.reject( new Error( 'No style found.' ) );
-	}
-	return new Promise( ( resolve, reject ) => {
-		const link = document.createElement( 'link' );
-		link.rel = 'stylesheet';
-		link.href = asset;
-		link.onload = () => resolve( true );
-		link.onerror = () => reject( new Error( 'Error loading style.' ) );
-		document.body.appendChild( link );
+		newNode.onload = () => resolve( true );
+		newNode.onerror = () => reject( new Error( 'Error loading asset.' ) );
+
+		document.body.appendChild( newNode );
+
+		// Resolve Stylesheets and Inline JavaScript immediately.
+		if (
+			'link' === newNode.nodeName.toLowerCase() ||
+			( 'script' === newNode.nodeName.toLowerCase() && ! newNode.src )
+		) {
+			resolve();
+		}
 	} );
 };
 
@@ -63,14 +62,47 @@ export function loadAssets( assets ) {
 }
 
 const controls = {
-	LOAD_ASSETS( { assets } ) {
-		const scripts = assets.map( ( asset ) =>
-			getPath( asset ).match( /\.js$/ ) !== null
-				? loadScript( asset )
-				: loadStyle( asset )
-		);
+	LOAD_ASSETS() {
+		/*
+		 * Fetch the current URL (post-new.php, or post.php?post=1&action=edit) and compare the
+		 * Javascript and CSS assets loaded between the pages. This imports the required assets
+		 * for the block into the current page while not requiring that we know them up-front.
+		 * In the future this can be improved by reliance upon block.json and/or a script-loader
+		 * dependancy API.
+		 */
+		return apiFetch( {
+			url: document.location.href,
+			parse: false,
+		} )
+			.then( ( response ) => response.text() )
+			.then( ( data ) => {
+				const doc = new window.DOMParser().parseFromString(
+					data,
+					'text/html'
+				);
+
+				const newAssets = Array.from(
+					doc.querySelectorAll( 'link[rel="stylesheet"],script' )
+				).filter(
+					( asset ) =>
+						asset.id && ! document.getElementById( asset.id )
+				);
 
-		return Promise.all( scripts );
+				return new Promise( async ( resolve, reject ) => {
+					for ( const i in newAssets ) {
+						try {
+							/*
+							 * Load each asset in order, as they may depend upon an earlier loaded script.
+							 * Stylesheets and Inline Scripts will resolve immediately upon insertion.
+							 */
+							await loadAsset( newAssets[ i ] );
+						} catch ( e ) {
+							reject( e );
+						}
+					}
+					resolve();
+				} );
+			} );
 	},
 };
 
diff --git a/packages/block-directory/src/store/test/actions.js b/packages/block-directory/src/store/test/actions.js
index 147ad2b1e415b3..b74f7f1a657725 100644
--- a/packages/block-directory/src/store/test/actions.js
+++ b/packages/block-directory/src/store/test/actions.js
@@ -158,31 +158,6 @@ describe( 'actions', () => {
 			} );
 		} );
 
-		it( 'should set an error if the plugin has no assets', () => {
-			const generator = installBlockType( { ...block, assets: [] } );
-
-			expect( generator.next().value ).toEqual( {
-				type: 'CLEAR_ERROR_NOTICE',
-				blockId: block.id,
-			} );
-
-			expect( generator.next().value ).toMatchObject( {
-				type: 'SET_ERROR_NOTICE',
-				blockId: block.id,
-			} );
-
-			expect( generator.next().value ).toEqual( {
-				type: 'SET_INSTALLING_BLOCK',
-				blockId: block.id,
-				isInstalling: false,
-			} );
-
-			expect( generator.next() ).toEqual( {
-				value: false,
-				done: true,
-			} );
-		} );
-
 		it( "should set an error if the plugin can't install", () => {
 			const generator = installBlockType( block );
 
diff --git a/packages/block-directory/src/store/test/controls.js b/packages/block-directory/src/store/test/controls.js
index 174cc5796c33ec..43d4f56ac0fab4 100644
--- a/packages/block-directory/src/store/test/controls.js
+++ b/packages/block-directory/src/store/test/controls.js
@@ -1,45 +1,21 @@
 /**
  * Internal dependencies
  */
-import { loadScript, loadStyle } from '../controls';
+import { loadAsset } from '../controls';
 
 describe( 'controls', () => {
-	const scriptAsset = 'http://www.wordpress.org/plugins/fakeasset.js';
-	const styleAsset = 'http://www.wordpress.org/plugins/fakeasset.css';
+	describe( 'loadAsset', () => {
+		const script = document.createElement( 'script' );
+		const style = document.createElement( 'link' );
 
-	describe( 'loadScript', () => {
 		it( 'should return a Promise when loading a script', () => {
-			const result = loadScript( scriptAsset );
+			const result = loadAsset( script );
 			expect( typeof result.then ).toBe( 'function' );
 		} );
 
-		it( 'should reject when no script is given', async () => {
-			expect.assertions( 1 );
-			const result = loadScript( '' );
-			await expect( result ).rejects.toThrow( Error );
-		} );
-
-		it( 'should reject when a non-js file is given', async () => {
-			const result = loadScript( styleAsset );
-			await expect( result ).rejects.toThrow( Error );
-		} );
-	} );
-
-	describe( 'loadStyle', () => {
 		it( 'should return a Promise when loading a style', () => {
-			const result = loadStyle( styleAsset );
+			const result = loadAsset( style );
 			expect( typeof result.then ).toBe( 'function' );
 		} );
-
-		it( 'should reject when no style is given', async () => {
-			expect.assertions( 1 );
-			const result = loadStyle( '' );
-			await expect( result ).rejects.toThrow( Error );
-		} );
-
-		it( 'should reject when a non-css file is given', async () => {
-			const result = loadStyle( scriptAsset );
-			await expect( result ).rejects.toThrow( Error );
-		} );
 	} );
 } );
diff --git a/packages/e2e-tests/specs/editor/plugins/block-directory-add.test.js b/packages/e2e-tests/specs/editor/plugins/block-directory-add.test.js
index b77f97f952601a..236d9314a5b699 100644
--- a/packages/e2e-tests/specs/editor/plugins/block-directory-add.test.js
+++ b/packages/e2e-tests/specs/editor/plugins/block-directory-add.test.js
@@ -123,6 +123,14 @@ const MOCK_BLOCKS_RESPONSES = [
 			'application/javascript; charset=utf-8'
 		),
 	},
+	{
+		// Mock the post-new page as requested via apiFetch for determining new CSS/JS assets.
+		match: ( request ) => request.url().includes( '/post-new.php' ),
+		onRequestMatch: createResponse(
+			`<html><head><script id="mock-block-js" src="${ MOCK_BLOCK1.assets[ 0 ] }"></script></head><body/></html>`,
+			'text/html; charset=UTF-8'
+		),
+	},
 ];
 
 function getResponseObject( obj, contentType ) {
@@ -180,8 +188,7 @@ describe( 'adding blocks from block directory', () => {
 		// Add the block
 		await addBtn.click();
 
-		// Delay to let block script load
-		await new Promise( ( resolve ) => setTimeout( resolve, 100 ) );
+		await page.waitForSelector( `div[data-type="${ MOCK_BLOCK1.name }"]` );
 
 		// The block will auto select and get added, make sure we see it in the content
 		expect( await getEditedPostContent() ).toMatchSnapshot();