diff --git a/src/validations.test.ts b/src/validations.test.ts
index 84daaee..dd61583 100644
--- a/src/validations.test.ts
+++ b/src/validations.test.ts
@@ -10,6 +10,7 @@ it.each`
 
 it.each`
   filename
+  ${'table.xlsx'}
   ${'book.epub'}
   ${'project.mpp'}
   ${'email.msg'}
diff --git a/src/validations.ts b/src/validations.ts
index 7b44727..011b053 100644
--- a/src/validations.ts
+++ b/src/validations.ts
@@ -13,6 +13,7 @@ const UNSUPPORTED_FILE_EXTENSIONS = [
   '.msg',
   '.mpp',
   '.epub',
+  '.xlsx',
 ];
 
 export function canBeConvertedToPDF(filename: string): boolean {