diff --git a/CHANGELOG.md b/CHANGELOG.md
index 29d794ba..32f3e5bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -37,6 +37,7 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 - Xls Reader changing grey background to black in Excel template [Issue #2147](Changing grey background to black in Excel template) [PR #2156](https://github.com/PHPOffice/PhpSpreadsheet/pull/2156)
 - Column width and Row height styles in the Html Reader when the value includes a unit of measure. [Issue #2145](https://github.com/PHPOffice/PhpSpreadsheet/issues/2145).
 - Data Validation flags not set correctly when reading XLSX files. [Issue #2224](https://github.com/PHPOffice/PhpSpreadsheet/issues/2224) [PR #2225](https://github.com/PHPOffice/PhpSpreadsheet/pull/2225)
+- Reading XLSX files without styles.xml throws an exception. [Issue #2246](https://github.com/PHPOffice/PhpSpreadsheet/issues/2246) 
 
 ## 1.18.0 - 2021-05-31
 
diff --git a/src/PhpSpreadsheet/Reader/Xlsx.php b/src/PhpSpreadsheet/Reader/Xlsx.php
index 5d379daf..2bff7e1e 100644
--- a/src/PhpSpreadsheet/Reader/Xlsx.php
+++ b/src/PhpSpreadsheet/Reader/Xlsx.php
@@ -395,10 +395,9 @@ class Xlsx extends BaseReader
         // Initialisations
         $excel = new Spreadsheet();
         $excel->removeSheetByIndex(0);
-        if (!$this->readDataOnly) {
-            $excel->removeCellStyleXfByIndex(0); // remove the default style
-            $excel->removeCellXfByIndex(0); // remove the default style
-        }
+        $addingFirstCellStyleXf = true;
+        $addingFirstCellXf = true;
+
         $unparsedLoadedData = [];
 
         $this->zip = $zip = new ZipArchive();
@@ -534,8 +533,14 @@ class Xlsx extends BaseReader
                         . "$xmlNamespaceBase/styles"
                         . "']";
                     $xpath = self::getArrayItem(self::xpathNoFalse($relsWorkbook, $relType));
-                    // I think Nonamespace is okay because I'm using xpath.
-                    $xmlStyles = $this->loadZipNonamespace("$dir/$xpath[Target]", $mainNS);
+
+                    if ($xpath === null) {
+                        $xmlStyles = self::testSimpleXml(null);
+                    } else {
+                        // I think Nonamespace is okay because I'm using xpath.
+                        $xmlStyles = $this->loadZipNonamespace("$dir/$xpath[Target]", $mainNS);
+                    }
+
                     $xmlStyles->registerXPathNamespace('smm', Namespaces::MAIN);
                     $fills = self::xpathNoFalse($xmlStyles, 'smm:fills/smm:fill');
                     $fonts = self::xpathNoFalse($xmlStyles, 'smm:fonts/smm:font');
@@ -593,6 +598,10 @@ class Xlsx extends BaseReader
                             // add style to cellXf collection
                             $objStyle = new Style();
                             self::readStyle($objStyle, $style);
+                            if ($addingFirstCellXf) {
+                                $excel->removeCellXfByIndex(0); // remove the default style
+                                $addingFirstCellXf = false;
+                            }
                             $excel->addCellXf($objStyle);
                         }
 
@@ -624,10 +633,13 @@ class Xlsx extends BaseReader
                             // add style to cellStyleXf collection
                             $objStyle = new Style();
                             self::readStyle($objStyle, $cellStyle);
+                            if ($addingFirstCellStyleXf) {
+                                $excel->removeCellStyleXfByIndex(0); // remove the default style
+                                $addingFirstCellStyleXf = false;
+                            }
                             $excel->addCellStyleXf($objStyle);
                         }
                     }
-
                     $styleReader = new Styles($xmlStyles);
                     $styleReader->setStyleBaseData(self::$theme, $styles, $cellStyles);
                     $dxfs = $styleReader->dxfs($this->readDataOnly);
diff --git a/tests/PhpSpreadsheetTests/Reader/Xlsx/XlsxTest.php b/tests/PhpSpreadsheetTests/Reader/Xlsx/XlsxTest.php
index a3776eb4..e1271b9a 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xlsx/XlsxTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xlsx/XlsxTest.php
@@ -4,7 +4,7 @@ namespace PhpOffice\PhpSpreadsheetTests\Reader\Xlsx;
 
 use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
 use PhpOffice\PhpSpreadsheet\Cell\DataValidation;
-use PhpOffice\PhpSpreadsheet\Document\Properties;
+use PhpOffice\PhpSpreadsheet\IOFactory;
 use PhpOffice\PhpSpreadsheet\Reader\Xlsx;
 use PhpOffice\PhpSpreadsheet\Shared\File;
 use PhpOffice\PhpSpreadsheet\Style\Conditional;
@@ -63,6 +63,49 @@ class XlsxTest extends TestCase
         }
     }
 
+    /**
+     * Test load Xlsx file without styles.xml.
+     */
+    public function testLoadXlsxWithoutStyles(): void
+    {
+        $filename = 'tests/data/Reader/XLSX/issue.2246a.xlsx';
+        $reader = new Xlsx();
+        $spreadsheet = $reader->load($filename);
+
+        $tempFilename = File::temporaryFilename();
+        $writer = IOFactory::createWriter($spreadsheet, 'Xlsx');
+        $writer->save($tempFilename);
+
+        $reader = new Xlsx();
+        $reloadedSpreadsheet = $reader->load($tempFilename);
+        unlink($tempFilename);
+
+        $reloadedWorksheet = $reloadedSpreadsheet->getActiveSheet();
+
+        self::assertEquals('TipoDato', $reloadedWorksheet->getCell('A1')->getValue());
+    }
+
+    /**
+     * Test load Xlsx file with empty styles.xml.
+     */
+    public function testLoadXlsxWithEmptyStyles(): void
+    {
+        $filename = 'tests/data/Reader/XLSX/issue.2246b.xlsx';
+        $reader = new Xlsx();
+        $spreadsheet = $reader->load($filename);
+
+        $tempFilename = File::temporaryFilename();
+        $writer = IOFactory::createWriter($spreadsheet, 'Xlsx');
+        $writer->save($tempFilename);
+
+        $reader = new Xlsx();
+        $reloadedSpreadsheet = $reader->load($tempFilename);
+        unlink($tempFilename);
+
+        $reloadedWorksheet = $reloadedSpreadsheet->getActiveSheet();
+        self::assertEquals('TipoDato', $reloadedWorksheet->getCell('A1')->getValue());
+    }
+
     public function testLoadXlsxAutofilter(): void
     {
         $filename = 'tests/data/Reader/XLSX/autofilterTest.xlsx';
diff --git a/tests/data/Reader/XLSX/issue.2246a.xlsx b/tests/data/Reader/XLSX/issue.2246a.xlsx
new file mode 100644
index 00000000..b1612208
Binary files /dev/null and b/tests/data/Reader/XLSX/issue.2246a.xlsx differ
diff --git a/tests/data/Reader/XLSX/issue.2246b.xlsx b/tests/data/Reader/XLSX/issue.2246b.xlsx
new file mode 100644
index 00000000..f33cbedc
Binary files /dev/null and b/tests/data/Reader/XLSX/issue.2246b.xlsx differ