diff --git a/src/wp-includes/class-wp-block-type.php b/src/wp-includes/class-wp-block-type.php
index 86f0ea21a2a3c..18170104cb9c5 100644
--- a/src/wp-includes/class-wp-block-type.php
+++ b/src/wp-includes/class-wp-block-type.php
@@ -510,6 +510,20 @@ public function prepare_attributes_for_render( $attributes ) {
 
 			$schema = $this->attributes[ $attribute_name ];
 
+			// Block metadata supports "rich-text" for editor attributes, but
+			// REST validation expects a valid JSON Schema type.
+			if ( isset( $schema['type'] ) ) {
+				if ( 'rich-text' === $schema['type'] ) {
+					$schema['type'] = 'string';
+				} elseif ( is_array( $schema['type'] ) ) {
+					foreach ( $schema['type'] as $type_index => $type ) {
+						if ( 'rich-text' === $type ) {
+							$schema['type'][ $type_index ] = 'string';
+						}
+					}
+				}
+			}
+
 			// Validate value by JSON schema. An invalid value should revert to
 			// its default, if one exists. This occurs by virtue of the missing
 			// attributes loop immediately following. If there is not a default
diff --git a/tests/phpunit/tests/blocks/wpBlockType.php b/tests/phpunit/tests/blocks/wpBlockType.php
index a73efa8ce8a7d..bb35b672c3dfc 100644
--- a/tests/phpunit/tests/blocks/wpBlockType.php
+++ b/tests/phpunit/tests/blocks/wpBlockType.php
@@ -254,6 +254,61 @@ public function test_prepare_attributes() {
 		);
 	}
 
+	/**
+	 * @ticket 61406
+	 */
+	public function test_prepare_attributes_validates_rich_text_attributes_as_strings() {
+		$doing_it_wrong = array();
+		$callback       = static function ( $function_name ) use ( &$doing_it_wrong ) {
+			if ( 'rest_validate_value_from_schema' === $function_name ) {
+				$doing_it_wrong[] = $function_name;
+			}
+		};
+
+		add_action( 'doing_it_wrong_run', $callback );
+
+		try {
+			$block_type = new WP_Block_Type(
+				'core/fake',
+				array(
+					'attributes' => array(
+						'content'         => array(
+							'type' => 'rich-text',
+						),
+						'caption'         => array(
+							'type'    => 'rich-text',
+							'default' => 'Default caption',
+						),
+						'nullableContent' => array(
+							'type' => array( 'rich-text', 'null' ),
+						),
+					),
+				)
+			);
+
+			$prepared_attributes = $block_type->prepare_attributes_for_render(
+				array(
+					'content'         => '<strong>include</strong>',
+					'caption'         => 5,
+					'nullableContent' => 'nullable include',
+				)
+			);
+		} finally {
+			remove_action( 'doing_it_wrong_run', $callback );
+		}
+
+		$this->assertSame( '<strong>include</strong>', $prepared_attributes['content'] );
+		$this->assertSame( 'Default caption', $prepared_attributes['caption'] );
+		$this->assertSame( 'nullable include', $prepared_attributes['nullableContent'] );
+		$this->assertSame(
+			array(),
+			$doing_it_wrong,
+			'rest_validate_value_from_schema() should not emit _doing_it_wrong() for rich-text attributes.'
+		);
+		$this->assertSame( 'rich-text', $block_type->attributes['content']['type'] );
+		$this->assertSame( array( 'rich-text', 'null' ), $block_type->attributes['nullableContent']['type'] );
+	}
+
 	/**
 	 * @ticket 45145
 	 */