diff --git a/src/cdk/testing/selenium-webdriver/selenium-web-driver-element.ts b/src/cdk/testing/selenium-webdriver/selenium-web-driver-element.ts
index 6435279f1c46..997bc7e703a1 100644
--- a/src/cdk/testing/selenium-webdriver/selenium-web-driver-element.ts
+++ b/src/cdk/testing/selenium-webdriver/selenium-web-driver-element.ts
@@ -161,7 +161,11 @@ export class SeleniumWebDriverElement implements TestElement {
   async setContenteditableValue(value: string): Promise<void> {
     const contenteditableAttr = await this.getAttribute('contenteditable');
 
-    if (contenteditableAttr !== '' && contenteditableAttr !== 'true') {
+    if (
+      contenteditableAttr !== '' &&
+      contenteditableAttr !== 'true' &&
+      contenteditableAttr !== 'plaintext-only'
+    ) {
       throw new Error('setContenteditableValue can only be called on a `contenteditable` element.');
     }
 
diff --git a/src/cdk/testing/testbed/unit-test-element.ts b/src/cdk/testing/testbed/unit-test-element.ts
index f441fd43af6b..0e2a5b21806b 100644
--- a/src/cdk/testing/testbed/unit-test-element.ts
+++ b/src/cdk/testing/testbed/unit-test-element.ts
@@ -193,7 +193,11 @@ export class UnitTestElement implements TestElement {
   async setContenteditableValue(value: string): Promise<void> {
     const contenteditableAttr = await this.getAttribute('contenteditable');
 
-    if (contenteditableAttr !== '' && contenteditableAttr !== 'true') {
+    if (
+      contenteditableAttr !== '' &&
+      contenteditableAttr !== 'true' &&
+      contenteditableAttr !== 'plaintext-only'
+    ) {
       throw new Error('setContenteditableValue can only be called on a `contenteditable` element.');
     }