diff --git a/src/wp-includes/pluggable.php b/src/wp-includes/pluggable.php
index ffcd2bdcc3..fdbfdea250 100644
--- a/src/wp-includes/pluggable.php
+++ b/src/wp-includes/pluggable.php
@@ -378,12 +378,16 @@ if ( ! function_exists( 'wp_mail' ) ) :
 		 */
 		if ( ! isset( $from_email ) ) {
 			// Get the site domain and get rid of www.
-			$sitename = wp_parse_url( network_home_url(), PHP_URL_HOST );
-			if ( 'www.' === substr( $sitename, 0, 4 ) ) {
-				$sitename = substr( $sitename, 4 );
-			}
+			$sitename   = wp_parse_url( network_home_url(), PHP_URL_HOST );
+			$from_email = 'wordpress@';
 
-			$from_email = 'wordpress@' . $sitename;
+			if ( null !== $sitename ) {
+				if ( 'www.' === substr( $sitename, 0, 4 ) ) {
+					$sitename = substr( $sitename, 4 );
+				}
+
+				$from_email .= $sitename;
+			}
 		}
 
 		/**
diff --git a/tests/phpunit/tests/mail.php b/tests/phpunit/tests/mail.php
index 66a613234b..8bf0a083c9 100644
--- a/tests/phpunit/tests/mail.php
+++ b/tests/phpunit/tests/mail.php
@@ -225,6 +225,28 @@ class Tests_Mail extends WP_UnitTestCase {
 		$this->assertStringContainsString( $expected, $mailer->get_sent()->header );
 	}
 
+	/**
+	 * Tests that wp_mail() returns false with an empty home URL and does not error out on PHP 8.1.
+	 *
+	 * @ticket 54730
+	 */
+	public function test_wp_mail_with_empty_home_url() {
+		$to      = 'address@tld.com';
+		$subject = 'Testing';
+		$message = 'Test Message';
+
+		// Multisite test runs.
+		add_filter( 'network_home_url', '__return_empty_string' );
+
+		// Single site test runs.
+		add_filter( 'home_url', '__return_empty_string' );
+
+		$success = wp_mail( $to, $subject, $message );
+
+		$this->assertFalse( $success, 'wp_mail() should have returned false' );
+		$this->assertGreaterThan( 0, did_action( 'wp_mail_failed' ), 'wp_mail_failed action was not called' );
+	}
+
 	/**
 	 * @ticket 30266
 	 */