diff --git a/aggregator.install b/aggregator.install
index c646717ec087bcc3a28cde92d66373c93e4146ba..1e063de73ce4a892bbad1d2a39a4ebce787e1354 100644
--- a/aggregator.install
+++ b/aggregator.install
@@ -61,6 +61,15 @@ function aggregator_update_8601() {
   $view_config->save();
 }
 
+/**
+ * Remove the teaser_length admin setting.
+ */
+function aggregator_update_8602() {
+  $settings = \Drupal::configFactory()->getEditable('aggregator.settings');
+  $settings->clear('items.teaser_length')
+    ->save();
+}
+
 /**
  * Determines whether the RSS view config has been altered from the default.
  *
diff --git a/config/install/aggregator.settings.yml b/config/install/aggregator.settings.yml
index be3a2017940a5fdb36519972da730288c7c65e28..20c446254471b3db07b3d41bf55923b1125d00c6 100644
--- a/config/install/aggregator.settings.yml
+++ b/config/install/aggregator.settings.yml
@@ -4,7 +4,6 @@ processors:
   - aggregator
 items:
   allowed_html: '<a> <b> <br> <dd> <dl> <dt> <em> <i> <li> <ol> <p> <strong> <u> <ul>'
-  teaser_length: 600
   expire: 9676800
 source:
   list_max: 3
diff --git a/config/schema/aggregator.schema.yml b/config/schema/aggregator.schema.yml
index eb6c006f62544fa7c529c23c21f0f626ed0888a9..7d14ad92e0f34f042944809e9cef41d63b63760b 100644
--- a/config/schema/aggregator.schema.yml
+++ b/config/schema/aggregator.schema.yml
@@ -23,9 +23,6 @@ aggregator.settings:
         allowed_html:
           type: string
           label: 'Allowed HTML tags'
-        teaser_length:
-          type: integer
-          label: 'Length of trimmed description'
         expire:
           type: integer
           label: 'Discard items older than'
diff --git a/migrations/d6_aggregator_settings.yml b/migrations/d6_aggregator_settings.yml
index a620f69eaf673ec33810e95a2b56120c3a14ed4d..ed2e82c83ccf808bdf8e7bac31d26bd5d08b979a 100644
--- a/migrations/d6_aggregator_settings.yml
+++ b/migrations/d6_aggregator_settings.yml
@@ -10,7 +10,6 @@ source:
     - aggregator_parser
     - aggregator_processors
     - aggregator_allowed_html_tags
-    - aggregator_teaser_length
     - aggregator_clear
     - aggregator_summary_items
   source_module: aggregator
@@ -19,7 +18,6 @@ process:
   parser: aggregator_parser
   processors: aggregator_processors
   'items/allowed_html': aggregator_allowed_html_tags
-  'items/teaser_length': aggregator_teaser_length
   'items/expire': aggregator_clear
   'source/list_max': aggregator_summary_items
 destination:
diff --git a/migrations/d7_aggregator_settings.yml b/migrations/d7_aggregator_settings.yml
index 3e4583ef84223f439ea256f10b9aecc7be8c31a8..8aadc1c62613eb75b4bc415d31d3ef900d477aa2 100644
--- a/migrations/d7_aggregator_settings.yml
+++ b/migrations/d7_aggregator_settings.yml
@@ -10,7 +10,6 @@ source:
     - aggregator_parser
     - aggregator_processors
     - aggregator_allowed_html_tags
-    - aggregator_teaser_length
     - aggregator_clear
     - aggregator_summary_items
   source_module: aggregator
@@ -19,7 +18,6 @@ process:
   parser: aggregator_parser
   processors: aggregator_processors
   'items/allowed_html': aggregator_allowed_html_tags
-  'items/teaser_length': aggregator_teaser_length
   'items/expire': aggregator_clear
   'source/list_max': aggregator_summary_items
 destination:
diff --git a/src/Plugin/aggregator/processor/DefaultProcessor.php b/src/Plugin/aggregator/processor/DefaultProcessor.php
index 53c42cc89133444ff6229908af738dcf6ebf0e02..7b43b1fc29f798ef593cc932d0fe1fa75db7a487 100644
--- a/src/Plugin/aggregator/processor/DefaultProcessor.php
+++ b/src/Plugin/aggregator/processor/DefaultProcessor.php
@@ -166,18 +166,6 @@ class DefaultProcessor extends AggregatorPluginSettingsBase implements Processor
       '#description' => t('Requires a correctly configured <a href=":cron">cron maintenance task</a>.', [':cron' => Url::fromRoute('system.status')->toString()]),
     ];
 
-    $lengths = [0, 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000];
-    $options = array_map(function ($length) {
-      return ($length == 0) ? t('Unlimited') : $this->formatPlural($length, '1 character', '@count characters');
-    }, array_combine($lengths, $lengths));
-
-    $form['processors'][$info['id']]['aggregator_teaser_length'] = [
-      '#type' => 'select',
-      '#title' => t('Length of trimmed description'),
-      '#default_value' => $config->get('items.teaser_length'),
-      '#options' => $options,
-      '#description' => t('The maximum number of characters used in the trimmed version of content.'),
-    ];
     return $form;
   }
 
@@ -186,7 +174,6 @@ class DefaultProcessor extends AggregatorPluginSettingsBase implements Processor
    */
   public function submitConfigurationForm(array &$form, FormStateInterface $form_state) {
     $this->configuration['items']['expire'] = $form_state->getValue('aggregator_clear');
-    $this->configuration['items']['teaser_length'] = $form_state->getValue('aggregator_teaser_length');
     $this->configuration['source']['list_max'] = $form_state->getValue('aggregator_summary_items');
     // @todo Refactor aggregator plugins to ConfigEntity so this is not needed.
     $this->setConfiguration($this->configuration);
diff --git a/tests/src/Functional/AggregatorAdminTest.php b/tests/src/Functional/AggregatorAdminTest.php
index 6e6ed2b2d7665130e6f90824bd866e505378aa3b..088aa4514b9e913521ec53c4d901e58869831026 100644
--- a/tests/src/Functional/AggregatorAdminTest.php
+++ b/tests/src/Functional/AggregatorAdminTest.php
@@ -31,7 +31,6 @@ class AggregatorAdminTest extends AggregatorTestBase {
       'aggregator_allowed_html_tags' => '<a>',
       'aggregator_summary_items' => 10,
       'aggregator_clear' => 3600,
-      'aggregator_teaser_length' => 200,
       'aggregator_fetcher' => 'aggregator_test_fetcher',
       'aggregator_parser' => 'aggregator_test_parser',
       'aggregator_processors[aggregator_test_processor]' => 'aggregator_test_processor',
diff --git a/tests/src/Functional/Update/AggregatorUpdateDeleteTeaserLengthSettingTest.php b/tests/src/Functional/Update/AggregatorUpdateDeleteTeaserLengthSettingTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..45c2dc0cba7b46e76c671bdcdce72021550c6599
--- /dev/null
+++ b/tests/src/Functional/Update/AggregatorUpdateDeleteTeaserLengthSettingTest.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace Drupal\Tests\aggregator\Functional\Update;
+
+use Drupal\FunctionalTests\Update\UpdatePathTestBase;
+
+/**
+ * @covers aggregator_update_8602()
+ * @group Update
+ * @group aggregator
+ */
+class AggregatorUpdateDeleteTeaserLengthSettingTest extends UpdatePathTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setDatabaseDumpFiles() {
+    $this->databaseDumpFiles = [
+      DRUPAL_ROOT . '/core/modules/system/tests/fixtures/update/drupal-9.4.0.bare.standard.php.gz',
+      __DIR__ . '/../../../fixtures/update/aggregator.php',
+    ];
+  }
+
+  /**
+   * Ensure the items.teaser_length setting is deleted.
+   */
+  public function testUpdateHookN(): void {
+    $this->runUpdates();
+    $settings = \Drupal::config('aggregator.settings');
+    $this->assertNull($settings->get('items.teaser_length'));
+  }
+
+}
diff --git a/tests/src/Kernel/Migrate/d6/MigrateAggregatorConfigsTest.php b/tests/src/Kernel/Migrate/d6/MigrateAggregatorConfigsTest.php
index bd3df58e5e8e7b5464639ef90056b32bf6ee87e5..2f520151d2126e7246d4178123b197abfcad374d 100644
--- a/tests/src/Kernel/Migrate/d6/MigrateAggregatorConfigsTest.php
+++ b/tests/src/Kernel/Migrate/d6/MigrateAggregatorConfigsTest.php
@@ -29,7 +29,6 @@ class MigrateAggregatorConfigsTest extends MigrateDrupal6TestBase {
     $this->assertSame('aggregator', $config->get('fetcher'));
     $this->assertSame('aggregator', $config->get('parser'));
     $this->assertSame(['aggregator'], $config->get('processors'));
-    $this->assertSame(600, $config->get('items.teaser_length'));
     $this->assertSame('<a> <b> <br /> <dd> <dl> <dt> <em> <i> <li> <ol> <p> <strong> <u> <ul>', $config->get('items.allowed_html'));
     $this->assertSame(9676800, $config->get('items.expire'));
     $this->assertSame(3, $config->get('source.list_max'));
diff --git a/tests/src/Kernel/Migrate/d7/MigrateAggregatorSettingsTest.php b/tests/src/Kernel/Migrate/d7/MigrateAggregatorSettingsTest.php
index 3b11917e224e9182d02cc673ec358b960f4c4d69..19809eb0339890f1c1f21fc0968e6f72d5b02633 100644
--- a/tests/src/Kernel/Migrate/d7/MigrateAggregatorSettingsTest.php
+++ b/tests/src/Kernel/Migrate/d7/MigrateAggregatorSettingsTest.php
@@ -27,7 +27,6 @@ class MigrateAggregatorSettingsTest extends MigrateDrupal7TestBase {
     $this->assertSame('aggregator', $config['parser']);
     $this->assertSame(['aggregator'], $config['processors']);
     $this->assertSame('<p> <div> <a>', $config['items']['allowed_html']);
-    $this->assertSame(500, $config['items']['teaser_length']);
     $this->assertSame(86400, $config['items']['expire']);
     $this->assertSame(6, $config['source']['list_max']);
   }