diff --git a/packages/block-library/src/html/modal.js b/packages/block-library/src/html/modal.js
index 2e6f3effc8688d..e081105fcbe68f 100644
--- a/packages/block-library/src/html/modal.js
+++ b/packages/block-library/src/html/modal.js
@@ -153,6 +153,7 @@ export default function HTMLEditModal( {
 										placeholder={ __( 'Write HTML…' ) }
 										aria-label={ __( 'HTML' ) }
 										className="block-library-html__modal-editor"
+										async
 									/>
 								</Tabs.TabPanel>
 								{ canUserUseUnfilteredHTML && (
@@ -167,6 +168,7 @@ export default function HTMLEditModal( {
 											placeholder={ __( 'Write CSS…' ) }
 											aria-label={ __( 'CSS' ) }
 											className="block-library-html__modal-editor"
+											async
 										/>
 									</Tabs.TabPanel>
 								) }
@@ -184,6 +186,7 @@ export default function HTMLEditModal( {
 											) }
 											aria-label={ __( 'JavaScript' ) }
 											className="block-library-html__modal-editor"
+											async
 										/>
 									</Tabs.TabPanel>
 								) }