diff --git a/src/wp-admin/includes/class-wp-site-health.php b/src/wp-admin/includes/class-wp-site-health.php
index 2ddfaadc4b39d..de0a77fb42c06 100644
--- a/src/wp-admin/includes/class-wp-site-health.php
+++ b/src/wp-admin/includes/class-wp-site-health.php
@@ -2802,7 +2802,8 @@ public function get_test_opcode_cache(): array {
 		$opcode_cache_enabled = false;
 		if ( function_exists( 'opcache_get_status' ) ) {
 			$status = @opcache_get_status( false ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- Warning emitted in failure case.
-			if ( $status && true === $status['opcache_enabled'] ) {
+			// OPcache reports `opcache_enabled` as false when only the file cache is in use, though that is still an active opcode cache.
+			if ( $status && ( true === $status['opcache_enabled'] || ! empty( $status['file_cache_only'] ) ) ) {
 				$opcode_cache_enabled = true;
 			}
 		}
diff --git a/tests/phpunit/tests/admin/wpSiteHealth.php b/tests/phpunit/tests/admin/wpSiteHealth.php
index 6080b477f54c3..5dd1198ec1d09 100644
--- a/tests/phpunit/tests/admin/wpSiteHealth.php
+++ b/tests/phpunit/tests/admin/wpSiteHealth.php
@@ -684,6 +684,7 @@ public function test_get_test_opcode_cache_return_structure() {
 	 * Covers: opcache enabled, disabled, not available, and opcache_get_status() returns false.
 	 *
 	 * @ticket 63697
+	 * @ticket 65921
 	 *
 	 * @covers ::get_test_opcode_cache()
 	 */
@@ -693,7 +694,7 @@ public function test_get_test_opcode_cache_result_by_environment() {
 		$opcache_enabled = false;
 		if ( function_exists( 'opcache_get_status' ) ) {
 			$status = @opcache_get_status( false ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- Warning emitted in failure case.
-			if ( $status && true === $status['opcache_enabled'] ) {
+			if ( $status && ( true === $status['opcache_enabled'] || ! empty( $status['file_cache_only'] ) ) ) {
 				$opcache_enabled = true;
 			}
 		}