diff --git a/src/wp-includes/class-wp-image-editor-imagick.php b/src/wp-includes/class-wp-image-editor-imagick.php
index 756fcce894..f29373f253 100644
--- a/src/wp-includes/class-wp-image-editor-imagick.php
+++ b/src/wp-includes/class-wp-image-editor-imagick.php
@@ -168,6 +168,10 @@ class WP_Image_Editor_Imagick extends WP_Image_Editor {
 				$this->image->setIteratorIndex( 0 );
 			}
 
+			if ( 'pdf' === $file_extension ) {
+				$this->remove_pdf_alpha_channel();
+			}
+
 			$this->mime_type = $this->get_mime_type( $this->image->getImageFormat() );
 		} catch ( Exception $e ) {
 			return new WP_Error( 'invalid_image', $e->getMessage(), $this->file );
@@ -751,6 +755,24 @@ class WP_Image_Editor_Imagick extends WP_Image_Editor {
 		return $saved;
 	}
 
+	/**
+	 * Removes PDF alpha after it's been read.
+	 *
+	 * @since 6.4.0
+	 */
+	protected function remove_pdf_alpha_channel() {
+		$version = Imagick::getVersion();
+		// Remove alpha channel if possible to avoid black backgrounds for Ghostscript >= 9.14. RemoveAlphaChannel added in ImageMagick 6.7.5.
+		if ( $version['versionNumber'] >= 0x675 ) {
+			try {
+				// Imagick::ALPHACHANNEL_REMOVE mapped to RemoveAlphaChannel in PHP imagick 3.2.0b2.
+				$this->image->setImageAlphaChannel( defined( 'Imagick::ALPHACHANNEL_REMOVE' ) ? Imagick::ALPHACHANNEL_REMOVE : 12 );
+			} catch ( Exception $e ) {
+				return new WP_Error( 'pdf_alpha_process_failed', $e->getMessage() );
+			}
+		}
+	}
+
 	/**
 	 * @since 3.5.0
 	 * @since 6.0.0 The `$filesize` value was added to the returned array.
diff --git a/tests/phpunit/data/images/test-alpha.pdf b/tests/phpunit/data/images/test-alpha.pdf
new file mode 100644
index 0000000000..1cbd4686e7
Binary files /dev/null and b/tests/phpunit/data/images/test-alpha.pdf differ
diff --git a/tests/phpunit/tests/image/editorImagick.php b/tests/phpunit/tests/image/editorImagick.php
index a8db8a3210..1209203904 100644
--- a/tests/phpunit/tests/image/editorImagick.php
+++ b/tests/phpunit/tests/image/editorImagick.php
@@ -641,4 +641,54 @@ class Tests_Image_Editor_Imagick extends WP_Image_UnitTestCase {
 
 		$this->assertNotWPError( $saved );
 	}
+
+	/**
+	 * Tests that the alpha channel of PDFs is removed from PDF previews.
+	 *
+	 * Only affects systems with Ghostscript version >= 9.14.
+	 *
+	 * @ticket 39216
+	 *
+	 * @covers WP_Image_Editor_Imagick::remove_pdf_alpha_channel
+	 */
+	public function test_remove_pdf_alpha_channel_should_remove_the_alpha_channel_in_preview() {
+		if ( ! wp_image_editor_supports( array( 'mime_type' => 'application/pdf' ) ) ) {
+			$this->markTestSkipped( 'Rendering PDFs is not supported on this system.' );
+		}
+
+		$test_file     = DIR_TESTDATA . '/images/test-alpha.pdf';
+		$attachment_id = $this->factory->attachment->create_upload_object( $test_file );
+		$this->assertNotEmpty( $attachment_id, 'The attachment was not created before testing.' );
+
+		$attached_file = get_attached_file( $attachment_id );
+		$this->assertNotEmpty( $attached_file, 'The attached file was not returned.' );
+
+		$rgb = array(
+			'r' => true,
+			'g' => true,
+			'b' => true,
+		);
+
+		// White.
+		$expected = array(
+			'r' => 1,
+			'g' => 1,
+			'b' => 1,
+		);
+
+		$check = image_get_intermediate_size( $attachment_id, 'full' );
+		$this->assertIsArray( $check, 'The intermediate size could not be retrieved.' );
+		$this->assertArrayHasKey( 'file', $check, 'The intermediate size file was not found.' );
+
+		$check_file = path_join( dirname( $attached_file ), $check['file'] );
+		$imagick    = new Imagick( $check_file );
+		$output     = array_map(
+			static function( $value ) {
+				return (int) round( $value );
+			},
+			array_intersect_key( $imagick->getImagePixelColor( 100, 100 )->getColor( true /* normalized */ ), $rgb )
+		);
+		$imagick->destroy();
+		$this->assertSame( $expected, $output, 'The image color of the generated thumb does not match expected opaque background.' ); // Allow for floating point equivalence.
+	}
 }